I can never be sure that Google and Bing (including DDG) are actually searching for what I tell them to, even after putting all my keywords in quotes, using int

I can never be sure that Google and Bing (including DDG) are actually searching for what I tell them to, even after putting all my keywords in quotes, using intext:"keyword", or using "verbatim" mode. I strongly suspect Google is substituting synonyms and "near synonyms" with irrelevant garbage to maximize Adsense yield. DDG and Bing are worse, as they ignore the quotes altogether rather than just most of the time. Yandex has a vastly smaller index and ignores quotes a lot of the time as well.