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Health Sciences Grey Literature: General Resources

Links to databases, search engines, and websites to some of the more commonly searched grey/gray literature in the health sciences.

Where to Begin?

The resources on this page provide a general starting point to searching for grey literature.

Here you will find links to databases that specifically collect and index grey literature documents.  The search engines found on this page have been designed to conduct  broad searches across global databases, including the deep web.  The preformulated search strategies have been designed to filter for specific types of grey literature such as non-governmental documents.

As the scope of grey literature is extremely broad, Sayre recommends considering the following questions in order to narrow down your search - slide 8:

  • Who are your stakeholders?
  • Government?
  • Non-government?
  • Academic?
  • What kinds of literature are you interested in?
  • Theses and dissertations?
  • Conference proceedings?
  • Reports?
  • Statistics?
  • What time period or geographic/geopolitical area is relevant to your search?

If you are conducting a systematic review, see Paynter's checklist of resources that covers three specific categories: regulatory information, trial registries, and abstracts & conferences.

Still have questions?  See additional guides or contact a librarian for help starting your search of grey literature.

Lists of Databases

The resources below contain lists of the many databases that can be searched for grey literature.


These resources broadly collect and index grey literature such as white papers, policy documents, summaries and more on global health topics.  The first two resources are the most commonly searched.  Additional resources are grouped geographically (American, European). Resources requiring USC login are listed last.   

PubMed Tools

PubMed databases, features, and preformulated search strategies.

Search Engines

The search engines below function similarly to Google, but contain features and filters useful for retrieving globally dispersed grey literature documents. These resources are organized first by broadest global perspective, and then by range of topic coverage from broadest to narrowest.  

Google Tools

Google databases and preformulated search engines.


These resources can be used to get in contact with researchers or to search for unpublished study information.