1. Keyword Search

If you just search for a word or phrase, PubMed will retrieve all references containing your search term – whether they are “about” your search term, or are about other topics, but have your query in another context

Check out this example from a search on treatment of common cold

Note that the article is about cultured cells and the words treatment, common and cold are in different areas of the abstract in completely different contexts!

Try some of these examples and see what kind of results you get