Actually, all too often, if I make even ONE refinement, I get the dreaded "No record" answer, even if I just saw several records that exactly meet my criteria. In fact we were just discussing this issue about 'New Search' on a message board for genealogist a few weeks ago. Many experienced genealogist consider it a serious problem.
I have been conducting Internet searches for nearly 20 years, back when we used Mosaic and Netscape. With a proper search engine, I know how to tweak a search.
Search is still the weakest link for Ancestry, by far, and a serious problem since they hold so many potentially valuable records.