PubMed search query:
biofeedback AND (beta blocker* OR andrenergic beta-antagonists) AND (hypertension OR blood pressure)
Filters: Adult: 19+ years (Age); Male (Sex)
Explanation of PubMed search query:
The best database searches are combinations of logical keywords and subject headings.
Keywords: biofeedback; beta blocker*
Note: The asterix* after blocker tells Pubmed to look for both singular and plural forms.
MeSH terms (PubMed subject headings): andrenergic beta-antagonists; hypertension (disease aspect); blood pressure (physiological aspect)
Why use parentheses in the search? (Think algebra.) Parentheses tell a database how to run a search correctly when it includes both AND and OR; PubMed reads the search above as: first find citations with either or both terms within each set of parentheses, and then combine these results with the rest of the search, i.e. the biofeedback aspect.
Filters/Limits: PubMed's filters appear on the left sidebar after you run the search; click Show more filters at the bottom of the left sidebar if you don't see the ones you need.