Search is keyword-based, like large-scale search is pretty much anywhere. Expecting "specifications" to match "spec" is expecting too much, same as expecting half your search to match a folder and the other half to match a file the folder is in.

The main thing to keep in mind is that search is content-based, not just filename. So instead, search for key terms you think are in the file, as opposed to focusing on folders/filenames. Start with one or two, then modify or add as necessary to narrow down.