Best Bet: PubMed
If you have one great article in hand, what can you do to find more articles like it?
Follow citations backward and forward
References (older than the article at hand)
"Citing Sources" or "Cited by" (newer than the article at hand)
Click on "Related" or "Similar" articles (in Google Scholar, PubMed, and other databases)
Follow the author (in databases and/or on social media)
Look at assigned "Subjects" or "Keywords"; use them to find more articles with that same subject.
Note: Google Scholar contains a wealth of journal articles, but the search interface is much less powerful than the library's subscription databases, and it won't effectively find substances and reactions.