The whole search doesn't show in the text box, but the full search string is:
tasers (document or report) “U.S. Department” site:.gov filetype:pdf after:2015
||tells Google to search for the word "tasers"
|(document OR report)
||tells Google to search for the words "document" OR "report" -- you need the parentheses and the Boolean operator "OR"
||the quotation marks tell Google only to find instances of these characters appearing together.
||tells Google to only search sites in the .GOV domain
|tells Google to only search for PDF files [Documents are most likely to be posted to the web as PDFs.]
||tells Google to only return pages posted to the web after 2015