Recently I've done an exact search by title to the file name (with and without the extension) and it's not found. It finds other documents and information from the parent site. Often they are not a good match and may only contain a small part of the search term. For instance, if I look for "alphabet soup" or "alphabet soup.doc" which exists on the sub-site where I'm searching, it finds "soup to nuts" and "learning the alphabet" on the parent site and other sub-sites, but not the document that has an exact match in the title.