Effectively searching MEDLINE is a skill acquired by practice. When performing your own search, use a variety of subject headings in various combinations. For example, we could have used "diving" and "reflex" in the previous example. Or perhaps, "diving", "reflex", and "heart rate". The search results using different combinations of subject headings will not be exactly the same. So if one combination of subject headings does not yield "useful" citations, try another combination.

For ideas of related subject headings, you can click on the button called "Find MeSH/Meta terms". Also, try using the button called "Analyze Search".

Good luck!