Skip to Main Content

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.

Structured Approach to Comprehensive Searching

Now that you've given some thought to what you will search and where you'll search, it's time to think about how to conduct the search. 

For the majority of health science comprehensive searches:

  1. Start with Ovid MEDLINE: Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE® Daily and Ovid MEDLINE® 1946-Present
  2. Search your concepts using a combination of subject headings and textwords, combined logically
  3. Perfect your MEDLINE search (see: Tips for Increasing Sensitivity)
  4. Translate your search into additional databases. Note: A librarian can help you select the best ones for your question.  

Use a "structured approach" to search comprehensively to:

  • edit and refine your search as you go
  • keep things clear and easy to understand
  • make it easy for your reader to follow 

In the below example, notice how a structured approach to this search makes the strategy clear and easy to understand.

Example : What is the role of therapy dogs in nursing homes? 


1. Start with concept 1:

  • First, the subject headings
  • Add textwords
  • Combine with 'or' to form Chunk 1

2. Add concept 2:

  • Combine subject heading(s) and textwords with 'or' to form Chunk 2

3. Combine concepts:

  • Combine Chunk 1 and Chunk 2 to find overlap!

Tips for searching databases w/ controlled vocabularies

  1. Search one concept at a time
  2. Map terms to subject headings
  3. Read the scope notes
  4. Look at the MeSH/subject heading tree
  5. When in doubt, explode but do not focus
  6. Use keywords as well as subject headings
  7. Combine terms with Boolean operators
  8. Gather keywords and subject headings from relevant results
  9. Limit results
  10. Save results & save search history

Using NOT as a Testing Tool

The NOT operator can be helpful in making decisions about your search strategy as you determine how to balance precision with sensitivity. You might use it in a number of ways, including:

  • If you are wondering how far to stretch your proximity operator
  • If you are considering including a specific synonym
  • If you are deciding whether to use a specific MeSH heading 

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.