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Natural Sciences: effective library research for dissertations: How to search

Online support to assist with planning and conducting your library dissertation research

 

 

To get the best results from online search services you need to input effective searches. 

The databases are not intelligent and will not understand your search topic.  

You need to devise and enter your search in a way that the databases can process to retrieve relevant search results for you.

It is useful to think of this as a three step process:

  1. Identify your search terms
  2. Combine your search terms
  3. Use search techniques to enhance your search

 

 

Search Strategy Worksheet

You can use the Search Strategy Worksheet to plan out and record your search strategy.

Explore the guidance below on these three areas and then test your knowledge with the quiz.

Activity

1. Identify your search terms

The exercise you conducted to map out your research topic/concepts will also help you produce appropriate keywords.  Think about those topics/concepts and produce lists of keywords that you could use to track down information on those topics.

Think carefully about suitable keywords and synonyms (alternative words that have a similar meaning) that will enable you to find manageable amounts of relevant material - not so many results that they are unmanageable and cause information overload, or so few that you retrieve insufficient information for you needs.

As with mapping out your research concepts, you may find it useful to adopt similar techniques -  e.g. brainstorming, words lists or mind maps to generate your keywords

Are there any alternative words and/or phrases you should include in your search in order to improve your search results? 

For example:
If you were researching the failure of small business in the UK you could use the following keywords: failure, success, demise, challenges, risk etc.

As well as searching for the UK, you might also search for United Kingdom, GBGreat Britain etc.

If you are looking for material on the Conservative Government you might also search for the Tory Government

When you are searching the global literature think about differences in spellings and terminology, and incorporate alternatives into your search strategy. Truncation and wildcard symbols can help with this.

For example:   globalisation (British spelling)  vs. globalization (American English spelling) 

 

Also think about differing terminology for the same subject. Subject terms and thesauri can help you with this.

For example:  holiday vs. vacation   /      underground vs.subway      

Consider whether  your area of research uses subject specific terminology, technical terms or other controlled vocabulary.

Use these specialised terms in your searching to improve your results.

If you do not know the standard terminology then the database subject index or thesaurus may help.

Have acronyms or abbreviations been used in the sources you have read? 

 These can be included in your search terms in order to findi matching results. 

For example: 

small and medium-sized enterprises and/or SMEs / AIDS and/or Acquired Immune Deficiency Syndrome / Doctor and/or Dr

Consider whether there are  key thinkers, writers, experts or analysts who are prominent or active in your research area.

It may be worth including these 'names' in your searches. 

Your background reading will prove helpful here.   

If you are searching across long time periods, remember that terminology changes over time.   New words appear, others change meaning so be prepared to reflect this in your search strategy.

For example:  tweet or twitter has a dual meaning: 

  1.  posting a short message to the Twitter social media platform
  2.  bird calls or short sharp sounds

This example illustrates how you might

1. pick out key terms from a research topic

2 break them down into keywords, alternative terms, variations and subject specific terminology that can be used for searching

2. Combine your search terms

It is possible to use a number of different keywords or search terms in a single search, by using operators. 

Operators link your search terms and define the relationship between them.

This enables more accurate searching and therefore more relevant results being returned. It also saves you time as you don't have to carry out numerous similar searches where just one or two search terms are changed each time.

                           Fig. 1                                                                                                                           Fig. 2

The three most commonly used operators are ANDORNOT.  These are known as Boolean operators. They can be used to broaden or narrow a search and to exclude unwanted search terms and concepts.

You can type these operators in between your search terms (Fig. 1) or you can use the drop down options in the Advanced Search option (Fig. 2). Look at the help pages on the database you want to use for specific guidance.   

Use AND to narrow your search.

Using AND between your search terms narrows your search as it  instructs the database that all your search terms must appear (in any order).

For example: quantum AND mechanics
                      - 
will only return results where both words are present

Because all search terms must be present, using AND makes the search more focused. 

In some (but not all) databases and search engines the AND is implied so if you enter multiple words the database will search for results which contain all/both words.

Use OR to broaden your search.

Using OR between search terms broadens your results as any or all of your search terms can be present.

For example: modelling OR modeling 
                      - will return results where either one or both of these words are present

It is extremely useful for finding synonyms or related concepts.

Using OR  enables you to carry out a number of similar searches in one go, saving you time.

Use NOT to narrow your search.

Using NOT narrows your search as it instructs the database to ignore results that contain particular words.

For example: artificial intelligence NOT robots
                      
- will return results that include artificial intelligence but do not  include robots

NOT  tends to be used less than the And and OR operators. 

Use it with care as you may exclude useful articles which cover a range of topics of relevance to you.

Databases usually process the Boolean operators in a logical order.

They typically recognise AND as the primary operator and will connect concepts with AND together first.

If you use a combination of AND and OR operators in one search, use parentheses (brackets) to group the OR words together so that your search is processed correctly.

For example:

If you want to find information on cloning humans and cloning sheep, use the following instruction:

cloning AND (sheep OR human)  - This will search for cloning AND sheep as well as cloning AND human

If you do not use the parentheses and search using the following:

cloning AND sheep OR human, your search will be processed as:

  • cloning AND sheep as one search
  • OR human as a secondary search - This means that your search results containing human would not be linked in any way to cloning.

Many databases offer the functionality to separate out your search terms, and this saves you having to add the parentheses. Sometimes you will have to access the Advanced Search for these options.

In this example from the Web of Science database, you can use the Basic search form to add multiple search lines by clicking on Add Another Field.

  

3. Use search techniques to improve your search

You can use search techniques to help improve your searching. By applying these techniques, you can increasereduce or improve the relevancy of your search results, making it easier to access to the right materials. 

Truncation is a technique that broadens your search to include various word endings and spellings.

To use truncation, enter the root of a word and put the truncation symbol at the end.

The database will return results that include any ending of that root word.

The asterisk * symbol is most commonly used for truncation. However, check out the help screens as  !, ?, or # may also be used.

For example:

entrepreneur* will find entrepreneurs, entrepreneurship, entrepreneurial etc.

child* will find child, childrenchildlikechildhood etc.

Use it with care to avoid finding too many alternatives.

Wildcards are similar to truncation but they are used to substitute for a single letter or no letter in a word.

They are useful for irregular plurals and for British/American English spellings.

They broaden your search by including variant word spellings.

The question mark symbol is most commonly used. However, check out the help screens as  ! , *, or # may also be used. 

For example:

wom?n will find woman and women

optimi?ation will find optimisation and optimization

model?ing will find modeling and modelling

Proximity searching can help to both increase or narrow your results. It can increase your results when "phrase searching" is too restrictive.

 

WITHIN Operator - Wx

Finds words within x number of words from each other, in the order they were entered.

Substitute the x with the number of words that may appear between  
 

ExampleHillary w2 Clinton 

Would find Hillary Clinton and Hillary Rodham Clinton

Would not find Clinton, Hillary

Phrase searching is the most limiting technique as it is used to specify that your terms must appear next to each other, and in the order you specify.

Phrase searching is commonly achieved by surrounding your phrase with quotation marks.

Always check the Database Help screens, as some databases may use different symbols.

Phrase searching examples:

"cylindrical pressure vessels"

"discrete frequency domain"

What are database fields?

Records in library catalogues and online databases are made up of fields containing pieces of bibliographic information which describe the item in details.

Fields differ between databases but common fields include:

  • author
  • title
  • journal title
  • abstract
  • publisher
  • date/year of publication
  • subject/descriptor

Why use field searching?

Field searching makes more search more focused and can be useful if you are overwhelmed by search results.

If you do not use field searching, databases usually run a keyword search against the full database record, leading to a very wide search.

For example, a keyword search for William Shakespeare will find items authored by William Shakespeare but also items that are about Shakespeare and his work.  An Author Search for William Shakespeare would be a more limited search.

You will usually need to use the Advanced Search option to easily access the field searching options.  

You can combine multiple fields using the boolean ANDORNOT operators.

The screenshot below illustrates field searching in the Business Source Complete database.

Note the wide choice of fields and how you can search across multiple fields for relevant content.  As Business Source Complete holds business related information it has a number of fields appropriate to that discipline.  You will find different fields in databases from other disciplines

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