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Gerstein Science Information Centre

Searching the Literature: A Guide to Comprehensive Searching in the Health Sciences

Students and researchers in the health sciences are often required to conduct comprehensive searches of the literature. Follow the steps in this guide to learn how this process works.

What Is Grey Literature?

Grey Literature is any literature that has not been published through traditional means. It is often excluded from large databases and other mainstream sources. Grey literature can also mean literature that is hard to find or has inconsistent or missing bibliographic information. 

Search grey literature to:

  • avoid bias
  • ensure that the review is as thorough as possible
  • find sources for negative results or brand new evidence
  • discover more references to published literature that your database search might have missed

CADTH's "Grey Matters" tool provides a list of organizations that produce grey literature. As well, the CRD guide and Chapter 6 of the Cochrane Handbook mentioned earlier in this guide include links to a number of grey literature sources.

Grey Literature Tutorial

Develop your Grey Literature Search Strategy

Finding grey literature can be tricky! The strategy you'll develop to find grey literature is very question- and objective-dependent, and can require quite a bit of creativity and dogged determination. Download and use the template below to see strategies to find and document your search for grey literature. 


  1. Search topic in Google and look through first 5-10 pages for relevant authorities, organizations or stakeholders.
    • Look at who publishes and/or stores relevant documents
  2. Review CADTH’s “Grey Matters” tool of health organizations
  3. Ask research team members for suggested organizations
  4. Browse the grey literature library page for sources of grey literature
  5. Use the below honeycomb to brainstorm potential authorities, organizations, or stakeholders relevant to your topic          


There are many different search strategies you can employ.


  • Targeted Website Browsing/Searching 
  • Advanced Google Targeted website searching
  • Grey Literature Database Search
  • Search Engine Searching 

The below links contain some grey literature resources for you to consider. 

Policy Documents

Databases & Catalogues of Grey Literature

This list provides only a few producers and collectors of grey literature. Do a thorough search for sources in your field.

Clinical Trials Databases



Government Documents

Government bodies frequently publish reports and studies on topics relevant to health science. In Canada, government bodies at both the national and provincial levels produce relevant material.

Institutional Repositories

Many institutions have institutional repositories, online databases of publications by their members. These can include publications by faculty and student dissertations and theses.


Conferences are nodes of new research, often featuring studies before they appear in journals.

Theses and Dissertations

Students conduct both systematic reviews and original studies for their theses and dissertations. These texts are not usually included in major databases.

U of T’s Theses and Dissertations in the Sciences research guide is an excellent resource, with links for both U of T theses and dissertations and those from other institutions.

Sources for Authorities

When searching for grey literature, it is recommended to browse individual websites of identified authorities on your subject. Use the links below to find websites for specific governmental agencies and departments. 

Contacting Experts and Authors

Often, writers of systematic reviews find that some data is left out of studies. In such cases, a good option is to contact the author of the study.

Experts in the field can also be rich sources of information. Talk to an expert to find out:

  • Studies or information you have missed
  • New aspects of your research topic to consider
  • Sources of grey lit

Negative Results

Newspapers and Magazines

Black and white stack of newspapers. creative commons 4.0; free to share and adapt.

“Newspapers B&W (4),” NS Newsflash

Newspapers and magazines can be helpful sources of non-academic information. While the information in newspapers might not be acceptable as a source of scientific evidence, newspapers can often point you to key references or provide a source of evidence for public opinion. 

U of T's research guide on Newspapers includes thorough information and some databases that also index magazines. You can also look up individual magazines in the library catalogue to determine our access.


Searching the Web

Sometimes, the best way to find grey lit is to search the Web. Different search engines have their own search algorithms that will pick up different results.

Another useful search engine is Duck Duck Go. Duck Duck Go does not collect user information and therefore results are not filtered based on your personal profile.

Closeup of computer keyboard

“keyboard detail view – macro,”  photosteve101 

Advanced Google

Use Advanced Search in Google

screenshot of advanced google with 'site or domain' and 'file type' circled

Look at the "Get More Out of Google" infographic for the full details

Optimize your Google Searches:

1. Combine keywords with boolean

  • OR: pull results that include either word [children or child or adolescent or young people]


2. Use quotation marks ( " " ) to search for phrases

  • Use around a phrase of two or more words ["alcohol abuse", "addictive behavior"]


3. Search a specific website rather than the entire Internet using site:

  • Get results from certain sites or domains []
  • To get results from multiple sites or domains, combine with OR [ OR]


4. Search for terms in location on webpage (intitle:)

  • Use intitle:term to restrict search results to documents containing term in the title.
  • For example, [intitle:addiction] will return documents that mention the word “addiction” in their titles


5. Search for particular types of documents (filetype:)

  • Specify the file type that your require (ex. pdf.) and be sure that this is no space between colon and file type [filetype:pdf]

Example search:

"alcohol abuse" ( OR filetype:pdf 



This work is openly licensed via CC BY-NC-SA 4.0For information on this guide contact Erica Nekolaichuk, Faculty Liaison & Instruction Librarian at the Gerstein Science Information Centre.