If you search any medications, use the generic name for them.

Good choice of keywords gives the best hits. You might have to put "human"in some because many animal/food processing papers exist on there. So if a term does not bring up much, try an alternate way of searching it. Authors can be searched Last name first then initials no punctuation.

Many PubMed papers do pop up on Google now, too.

Some abbreviations like RSD don't bring all papers you are searching for. And some abbreviations can stand for more than one thing. Example GLA, or ALA, can bring up confusing results.
SAMe doesn't get what one needs either. Must use s-adenosylmethionine for that search.

I lately also do Wiki searches. Sometimes there are clues there that you can then further explore on PubMed. Wiki has become better and more reliable lately IMO. I never used to use it as much as I do now.