Better PDF text search engine than Acrobat?

MY PROBLEM: Often when I search a large PDF document for information I will get multiple hits when I search for a specific single word (or phrase). But often I am searching for two or more words that appear close together. If I type in the the phrase I want, it often comes back with zero results because the phrase I entered does not appear in the document as I typed it. 

AN EXAMPLE: I'm search for camera settings in a 350+ page PDF user manual and I would like to know the different burst (multiple shots) rate options. I type in "burst rate". There are zero results for this exact phrase ... BUT ... I don't need the exact phrase. It may turn out that the title of the page is "Burst Settings" and on that page is the word "rate" and the answer to my question. 

MY QUESTION: Is there a PDF search engine (maybe Acrobat?) that will allow me to enter two or more search words and it will order the results depending on how close (e.g., in character spaces) the search words I entered are in the document. One would think that this is not difficult to program. Also, with so many programs using "AI" these days, this task shouldn't be that hard???

Maybe Acrobat (the paid version) will do this? If not, any suggestions?

Thanks,

- Simon