If you are coming up short on results, there are a a few strategies that may help expand your search.
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.
|contraception AND Obamacare
|contraception AND (Obamacare OR "Affordable Care Act" OR ACA OR "Patient Protection and Affordable Care Act" OR PPACA)
"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".
PubMed automatically explodes MeSH terms to include narrower subject headings.
Truncation symbols in a database (such as "*" or "?") allow you to search on a root word and include plurals or variants.
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.
"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.
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.