Skip to main content

Physical Therapy

Guide to locating research evidence and tools for Physical Therapy students and faculty.

Strategies for Broadening a Search

If you are coming up short on results, there are a a few strategies that may help expand your search.

1. Harvest Additional Synonyms

Survey your initial search results to identify any additional keywords or synonyms that might broaden the search.  Consider acronyms, spelling variants and alternative phrases and integrate them into the search with the Boolean operator OR.  

Integrating synonyms with the Boolean operator OR will typically increase the number of search results
Search Query Results
contraception AND Obamacare 91
contraception AND (Obamacare OR "Affordable Care Act" OR ACA OR "Patient Protection and Affordable Care Act" OR PPACA) 219

2. "Explode" Your Subject Headings

"Exploding" a subject heading means asking the database to retrieve articles with that subject heading, as well as articles that have been tagged with terms that are under that term in the subject heading tree.  For instance, in CINAHL, exploding the term "Telehealth" would include narrower terms like "Telemedicine" and "Telenursing".

CINAHL Subject Thesaurus shows narrower terms under "telehealth" (e.g. telemedicine, teledentistry)


Searching with a subject heading exploded retrieves a greater number of results
Search Query Results
(MH "Telehealth")  9,500
(MH "Telehealth+")  26,000

PubMed automatically explodes MeSH terms to include narrower subject headings.

Also see:

3. Truncate One or More Search Term

Truncation symbols in a database (such as "*" or "?") allow you to search on a root word and include plurals or variants.

For example:

  • diabet* retrieves diabetes OR diabetic OR diabetogenic
  • autis* retrieves autism OR autistic
  • nurs* retrieves nurse OR nursing OR nursing

Be aware that truncation may also retrieve false hits. For instance, a search on nurs* would also retrieve “nursery school”.  Using a shorter root word will likely map to more variants, while using a longer root word will be more specific.  


4. Snowballing / Pearl Growing

"Citation pearl growing" uses a relevant source to lead to more sources on a topic.  In the database records, look for link to "related" articles or “find similar results." 

Also consider mining the reference list to follow up on citations that may be relevant. Review articles, including systematic reviews, can be a goldmine of related literature.  

Similarly, you can perform 'cited reference searching' to track additional articles that have cited a particular, relevant study.  

In expanded a search, it is useful to mine the reference of relevant articles for additional sources, as well as perform cited reference searching


Finally, if you find that much of the relevant literature on your topic of interest is published in a small handful of journals, you could also "hand search" the tables of content for those journals by accessing them through the library catalog.