My search was: jwt web toolkit
The search page itself had no Google ads on it.
The top link was the homepage for the toolkit project. There were no ad links on the page.
The second and third links were for wikipedia, which contained no Google ads.
The fourth link did have Google ads on it. The fifth and sixth lengths did not. The seventh link did.
I tried again with a different set of search terms: neutron spin echo
The top of the page did contain a link to Google Scholar, followed by three links to pay walled articles. I am not aware of any profit agreement between Google and the publishers, but it wouldn't surprise me to learn that it's there.
The remaining links were either to pages containing no advertising (Google or otherwise) or to more pay walled articles. Short of Google have a relationship with the publishers, Google again made no money on this search.
For the record, I don't have an ad-blocker turned on, so I would see ads if they were there.