This logic is used in search fields in databases. Each database is different, but most adhere to this logic in the same or similar ways.
Subject headings are assigned words or phrases used in a database to organize articles and more.
You may also look at the Major Subjects and Minor Subjects (CINAHL) and keywords and MeSH terms (PubMed) in any article of interest to see if there are terms that would be more helpful in your search.
Looking at similar articles may bring other relevant articles to your searching, but you will need to limit the search again by your keywords, dates, source/article type, etc.
CINAHL Subject Headings and Major Subjects
PubMed Keywords and MeSH Terms