LibGuides: Alternatives to United States NLM Resources: Home

Introduction

NCBI stands for "The National Center for Biotechnology Information". NCBI is part of the United States National Library of Medicine (NLM), at the National Institutes of Health (NIH), which is a US government agency for biomedical and public health research. NIH, in turn, is part of the Department of Health and Human Services (HHS), an executive department of the U.S federal government.

The National Library of Medicine produce and maintain a number of free-to-access resources which are heavily used within the health sciences. These include (among others):

PubMed is maintained by NCBI, and largely consists of the database Medline. It covers all aspects of human medicine and related biomedical research, including comprehensive information on drugs and toxicology, clinical medicine, biotechnology and bioengineering, health affairs, dentistry, psychiatry and forensic medicine. It is a key resource for academic research within the health sciences. Access to PubMed is free, but not all articles hosted on it are publicly available.
PubMed Central (PMC) is a digital repository for open access biomedical and life sciences articles. All material in this repository is freely available to the public.
ClinicalTrials.gov is a registry of clinical trials from countries across the world.

For further guidance on the differences between Medline, PubMed and PMC, see this article.

Ongoing threats to PubMed's reliability

Since January 2025, the Trump administration have initiated large-scale restructures to many government departments. In HHS, this includes an overall loss of around 20,000 employees, a reduction in divisions (from 28 to 15), and a dramatic change in priorities including moving away from vaccine research and projects deemed to be aligned with Diversity, Equity, and Inclusion. A list of grants relating to these topics that have been terminated are available here. Additionally, large numbers of web pages and datasets have been deleted or modified across a number of U.S federal agencies. Find a detailed list of these on this Wikipedia page.

This upheaval and change within the U.S government may result in loss of material from resources such as PubMed, or changes to the reliability of its indexing policies. It is possible that the site infrastructure may become increasingly unstable, or we may encounter intermittent or complete loss of access. More generally, the future quality of healthcare research coming out of the U.S is also likely to be affected. There is emerging evidence that other NIH-funded databases/repositories are undergoing alteration: currently, a number of federally funded repositories of human data have banners on their websites stating that they are "under review for potential modification in compliance with Administration directives". Meanwhile, the NLM page which listed members of the LSTRC (Medline Literature Selection Technical Review Committee) is no longer available.

As such, it is important to be aware of alternatives to the above resources, and to stay abreast of any changes to access and reliability. This guide provides introductory explanations, links to further reading, and suggestions for subscription and open-access alternatives to affected resources.

This guide is in its initial stages, and subject to changes. Please note that as of 14/04/2025, there has been no reported change to access to PubMed or to its indexing policies.

Collection development policies and guidelines

UPDATES

As of April 2025, the NLM page which listed members of the LSTRC (Literature Selection Technical Review Committee) is not available. The LSTRC meet 3 times a year to review journals which have applied to Medline. A previous list, captured on the Internet Archive wayback machine, is here.

Collection Development Guidelines of the National Library of Medicine
NLM Catalog: Journals referenced in the NCBI Databases
Use this to determine the Medline indexing status of journals.
Journal selection for Medline
Information on scientific and editorial quality assessment for inclusion of journals in Medline
Journal selection for PMC
Information on scientific and editorial quality assessment for inclusion of journals in PMC

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Indexing in PubMed - Medical Subject Headings

BBC Bitesize: US political institutions and government decision-making
A short introduction to the basic overall structure of the U.S government
Federal Depository Library Program
Detailed explanation of the structure of the U.S. Government, with a list of all executive departments (such as the Department of Health and Human Services), and their websites.
DOGE
Wikipedia article on DOGE, the new "Department of Governmental Efficiency", which was formed on January 20th 2025.

Department of Education

President Trump signed an executive order aimed at dismantling the Department of Education on 20 March 2025; however, this cannot be accomplished legally without congressional approval. The American Educational Research Association (AERA) and the Society for Research on Educational Effectiveness (SREE) have filed a lawsuit against the Department of Education, which can be viewed here.

The database ERIC (Education Resources Information Center) is a searchable index of scholarly education literature, which is sponsored by the U.S Department of Education. A discussion post in the ACRL Evidence Synthesis Methods Interest Group states that some journals are being deselected from ERIC, with a reduction of 45% to the collection from 24th April 2025. This appears to come as a result of funding cuts engineered by the Department of Government Efficiency (DOGE). As of April 22nd, it has been reported on the website Governing that no new material at all will be added to the database from 23rd April onwards.

A document tracking journals which will no longer be indexed by ERIC, together with emails sent to journal editors explaining their deselection, is available here.

Below are a selection of university library guides and posts on the issue:

This article provides useful information on how to access archived material from ERIC via the Internet Archive.

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Institute of Museum and Library Services

IMLS is an independent agency of the U.S federal government. On March 31st 2025, all staff at the Institute of Museum and Library Services were placed on administrative leave.

Read the American Alliance of Museum's press release on this below:

AAM (2025) "AAM Statement on the placing of IMLS staff on administrative leave", 31 March.

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United States Agency for International Development (USAID)

An agency responsible for foreign aid and development assistance, USAID has historically been one of the world's largest aid agencies, and it has a vast impact on global health. For example, the World Food Programme relies on U.S funding for half of its budget. The Trump administration have frozen almost all foreign aid and placed nearly all USAID employees on administrative leave. Programmes distributing food, medical supplies and clean water in various countries were abruptly halted. As of 09 April 2025, some of the World Food Programme humanitarian aid contracts which had been cancelled were restored, but not all. Court cases are ongoing which consider the legality of the administration's actions.

Please note that this section is not exhaustive, and is focused on changes to departments and agencies that are directly relevant to global health. It is not intended to cover all changes to U.S government made by the Trump administration.

Bastian, H. (2025) "What if We Can't Rely on PubMed?". Absolutely Maybe, 14 Feb.
For an excellent introduction to the current concerns around PubMed's stability, read this article by Hilda Bastian.
Dyer, O. (2025). "What is happening to the US National Institutes of Health?" BMJ, 28 March.
Falconer, J. (2025). "Alternative Sources of US Federal Government Information".
This blog post from the London School of Hygiene and Tropical Medicine library provides a comprehensive overview of the situation, and is being continually updated.
MLA (2025). "Protecting Access to Health Information: the Critical Role of Libraries, NLM, and NIH Funding".
Statement from the MLA (the U.S-based Medical Library Association), on the loss of government health data.
Wikipedia. "2025 United States government online resource removals."

The library subscribes to a wide range of health sciences databases, each with their own specific areas of focus. Browse these through the library's A-Z Databases list.

Access to the database Medline is available from a range of sources which the library subscribes to, including through Ovid. Have a look at the library's "Ovid" guide for some information about how to use this resource.

Medline can also be accessed through:

This means that access to material currently already on Medline that may be removed from PubMed will still be available via other sources. However, should indexing policy change within PubMed, this in turn will affect the material that is added to Medline in the future, regardless of mode of access.

Databases which use PubMed

Material from PubMed/Medline forms a substantial part of a number of well-used databases. These include (but are not limited to):

Europe PMC
Embase
CENTRAL (Cochrane Register of Controlled Trials)
Epistemonikos
TRIP

For some of these databases, it is possible to make a rough estimate of the percentage of material that comes from PubMed. Embase have provided a detailed breakdown (listed in adjacent tab), while CENTRAL and Europe PMC allow filtering of results by source, enabling the percentages to be worked out manually. In others, this is not possible.

Below is a graphic illustrating the percentages of material taken from PubMed in some databases. It is a rough estimate for visualisation purposes only.

The Cochrane Register of Controlled Trials pulls information from a variety of sources, including Pubmed, Embase, ClinicalTrials.gov, ICTRP, CINAHL, and other unnamed sources. Further information about this is here.

It is possible to restrict search results in CENTRAL to specific sources either by using the filters on the left-hand side of the results page, or by using specific search syntax (eg. embase:an).

Using this method, a rough estimate of percentages of material from each source has been calculated as below

CENTRAL	Total number	Percentage
PubMed, Embase and CINAHL	402434	18.09%
PubMed Only	543535	24.43%
Embase only	373233	16.78%
CINAHL only	33941	1.53%
ICTRP	281440	12.65%
CT.gov	275939	12.40%
Other	314066	14.12%
ALL	2224588

CENTRAL

Embase is a large biomedical and pharmacological database, produced by Elsevier. Embase also has a Medline supplement.

Elsevier have provided the following information about how Embase is indexed and sourced, and the effect on the database of any changes to Medline.

"As of January 1, 2025, Embase includes 8,386 journals:

39% (3,257 journals): Embase unique – sourced directly from publishers and indexed with Emtree.
40% (3,359 journals): Embase/MEDLINE – covered in both Embase and Medline, but Elsevier sources the journal content directly from the publisher and indexes it using Emtree.
21% (1,770 journals): MEDLINE unique – sourced via NIH, with MeSH terms mapped to Emtree.

Embase also covers preprints from BioRxiv, MedRxiv and SSRN, as well as conference abstracts, which are unaffected by NIH.

If MEDLINE production stops:

Embase/MEDLINE content: MeSH terms will no longer be available, but journals will remain indexed with Emtree.
MEDLINE unique content: We will no longer receive this content but are working to source it directly from publishers and remove the dependency on NIH.

All existing content in Embase, including MEDLINE unique content, will persist unless legally required to be removed.

In summary: Embase users continue to have access to the majority of up-to-date content regardless of any potential disruptions at NIH. We are also actively reducing remaining dependencies to maintain Embase as the most trusted resource for biomedical insights."

Europe PMC is not a direct mirror of PubMed, but it sources approximately 86% of its total material from it. The rest comprises mostly of biological patents and preprints. Find out more about where EuropePMC sources its content on its help pages, here.

Source	Percentage
PubMed/Medline NLM	84.23%
Biological Patents	9.23%
Preprints	2.02%
Agricola	2.01%
PubMed Central	1.80%
EthOs Theses	0.39%
Chinese Biological Abstracts	0.31%
NHS Evidence	0.01%
CiteXplore	0.01%
Europe PMC Book metadata	0.00%

*worked out by searching for each source individually, eg. SRC:"MED". The total number of entries can be found with SRC:*

Alternative Open Access Resources

DiTA, Diagnostic Test Accuracy
"DiTA is the Diagnostic Test Accuracy database, a free database that indexes primary studies of diagnostic test accuracy and systematic reviews of diagnostic test accuracy studies related to physiotherapy practice."
Epistemonikos
A multilingual database of health evidence, particularly useful for identifying systematic reviews. Pulls from a range of sources including (but not limited to) PubMed.
Europe PMC
"Europe PMC provides comprehensive access to life sciences literature from trusted sources. It's available to anyone, anywhere for free. With Europe PMC you can search and read 45.6 million publications, preprints and other documents enriched with links to supporting data, reviews, protocols, and other relevant resources."
Global Index Medicus
The Global Index Medicus (GIM) provides worldwide access to biomedical and public health literature produced by and within low-middle income countries. The main objective is to increase the visibility and usability of this important set of resources. The material is collated and aggregated by WHO Regional Office Libraries on a central search platform allowing retrieval of bibliographical and full text information. Searchable in Arabic, Chinese, English, French, Russian and Spanish.
LILACS
Latin American and Caribbean Health Sciences Literature. Search in English, Spanish or Portuguese.
PEDro, Physiotherapy Evidence Database
PEDro "is a free database of over 64,000 trials, reviews and guidelines evaluating physiotherapy interventions".
TRIP
"Tip is a clinical search engine designed to allow users to quickly and easily find and use high-quality research evidence to support their practice and/or care". TRIP is freely available; however, there is also a paid Pro version, which the University of Exeter subscribes to.

Multidisciplinary

BASE
"BASE is one of the world's most voluminous search engines especially for academic web resources. The index contains more than 400 million records from more than 11,000 content providers. You can access the full texts of about 60% of the indexed records for free (Open Access). BASE is operated by Bielefeld University Library."
CORE
Based at the UK's Open University, CORE is a service which provides the world's largest collection of open access research papers.
DOAJ: Directory of Open Access Journals
Index of open-access journals from around the world, managed by team members from 45 different countries, speaking 36 languages.
The Lens
A free searchable patent and scholarly literature database covering science and technology.
OpenAlex
"We index over 250M scholarly works from 250k sources, with extra coverage of humanities, non-English languages, and the Global South."
OSF Preprints
An Open Science Framework initiative that supports the sharing of preprints from a range of disciplines.
Scielo (Scientific Electronic Library Online)
A multidisciplinary platform covering Latin America, the Iberian Peninsula, and South Africa.

WHO International Clinical Trials Registry Platform
Access to information about ongoing and completed clinical trials. It provides a searchable database containing the trial registration data sets made available by data providers around the world.
EU Clinical Trials Register
Information on interventional clinical trials on medicines conducted in the European Union (EU), or the European Economic Area (EEA) which started after 1 May 2004.

Data Lumos
"DataLumos is an ICPSR archive for valuable government data resources. ICPSR has a long commitment to safekeeping and disseminating US government and other social science data. DataLumos accepts deposits of public data resources from the community and recommendations of public data resources that ICPSR itself might add to DataLumos. Please consider making a monetary donation to sustain DataLumos."
The Data Rescue Project
"The Data Rescue Project is a coordinated effort among a group of data organizations, including IASSIST, RDAP, and members of the Data Curation Network. Our goal is to serve as a clearinghouse for data rescue-related efforts and data access points for public US governmental data that are currently at risk. We want to know what is happening in the community so that we can coordinate focus. Efforts include: data gathering, data curation and cleaning, data cataloging, and providing sustained access and distribution of data assets."
Policy Commons 2025 Open Collection
"The Policy Commons 2025 Open Collection is an initiative to rescue and preserve materials from government organizations facing the removal of public information and data—reports, blog posts, videos, and podcasts. Coherent will archive, assign permanent unique identifiers, and index the materials for discovery through Google Scholar and academic databases. Each item will be enriched with detailed metadata—and made openly available to the public."
Public Environmental Data Partners
"The Public Environmental Data Partners are committed to preserving and providing public access to federal environmental data. We are a volunteer coalition of several environmental, justice, and policy organizations, researchers across several universities, archivists, and students who rely on federal datasets and tools to support critical research, advocacy, policy, and litigation work."
Restored CDC
A recreation of the CDC (centers for disease control and prevention) website as it was when Trump was inaugurated.
The Wayback Machine (Internet Archive)
A digital archive of the internet - the wayback machine saves webpages, so that users can view deleted or altered material as it appeared at different points in the past.

University of Exeter. "Grey Literature".
The Library's Grey Literature guide provides a range of discovery tools for various types of grey literature, including online repositories, clinical trial registries, datasets and more.
University of Lancaster Library. "Decolonising Literature Searching".
The University of Lancaster have an excellent and detailed guide on "decolonising literature searching", which highlights the gaps in established literature databases for resources on or from the Global South. A large number of alternative databases and repositories are listed.