How can I return the top-ranking .pdf file (on Google) for any keyword?

Hello everyone, new here. I'm Chris.

I'm trying to get SEO Tools to return the top-ranking .pdf file (on Google) for any keyword.

For example, the query: filetype:pdf & "computer repair"

I found a search option like this for Bing and for Yahoo, but neither works when I use quotation marks for exact match. I couldn't find an option for Google results.

Any suggestions?