I was G searching altering gut biome and the top slot was an inset offering "Scholarly articles for altering gut biome" --which led to scholar.google.com. I only have a vague recollection of this specialized search.  Seems like it would be handy for sifting through research on -say- supplements, emerging tech, bleeding edge mathematics, etc.  Anybody used it?

My son uses that all the time.

It is where he gets his supporting research studies for his blog posts.

Yeah, I use it a fair bit. I used to use Medline or whatever, but Google Scholar is more likely to lead you to sources that you can actually read (i.e. not behind a paywall). But if you want a comprehensive search, the specialized databases in a given field are likely to be a better place to start