Library Search enables you to find high quality resources from a wide range of sources in a single search.
BUT - be aware that ...
Use the Library Search service in combination with the A–Z Databases List to access all the content that is available to you.
Be aware that as the large research databases index the global literature so not all the resources you find via these large global databases will be available to you via the Library. Use the library catalogue to check on titles.
Think of the Library Search and A-Z Databases Lists as complementary services and choose whichever suits your research need at the time.