USA.gov no longer features an Advanced Search page. Unfortunately, this does not come as a surprise as USA.gov is "powered by" Bing - and Bing shed its Advanced Search page awhile ago.

Previously, USA.gov's Advanced Search page provided a "fill-in-the-box"-type interface (similar to Google's Advanced Search page) that allowed you to create sophisticated, targeted searches through the USA.gov index.

You can still perform more precise advanced-type searches at USA.gov if you use specific search syntax to give USA.gov instructions on how to target your search. For more tips on searching USA.gov/Bing, see this post.