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Systematic Reviews: Selecting databases


 flipping through book

Knowing where to look for studies is key to a successful review. Below you will find information on the most relevant databases, as well as places to search for unpublished literature and a guide to hand searching.

Top Databases

essential databases

You should include these databases in your search:

You should also search:

►*Note: Scopus covers Embase, but does not provide Emtree. Gumberg does not currently provide access to Web of Science; contact your librarian for assistance. 

Additional Databases

additional databases

The following are a selection of additional databases that should be searched in order to reduce language biases:

Selected Specialized Databases

selected specialized databases

Search these additional databases depending on your subject.

Below you will find a sampling of selected subject-specific databases. Contact your librarian for information on additional databases.

Grey Literature

grey literature


To prevent publication bias, you need to search for grey (or gray) literature, that is, literature that has not been published. 

The list of databases below is a good place to start; you should also look at conference abstracts as well as institutional and disciplinary repositories.

Hand Searching

hand searching


Hand Searching is a manual process of looking through journals page by page, often involving looking at each reference in each journal article found. Hand search to find studies that may not have been indexed in the databases.

You should hand search conference papers as well as the most relevant journals in your field.

Make sure you document the hand searching process.

Ask your librarian for assistance.

To learn more about why hand searching is so important, read this 2005 article from Armstrong et al.: It's in your hands: The value of hand searching...

Cochrane offers information on hand searching as well.

more places to search

more places to search


To find clinical trials, search National Institute of Health's Clinical Trials registry and York Health Economics Consortium's Finding Clinical Trials

Examine reference lists: when you find relevant studies, look at the works cited to find more studies to include in your review.

A citation search can also help find additional studies. Eloise Flood at Pace University has a great guide to help with citation searching.

Perform an Internet search: using a variety of web browsers, search for your topic. This may lead you to individuals or organizations who have done studies pertaining to your question. You can then contact these people and places to see if they have any unpublished studies you would want to include.