Using the SE search tool I searched for 'wavelets', and got one set of questions, then I searched for 'wavelet' and got an overlapping set. Then I searched for 'wavelet*' and got another set. I didn't realise that searching was precise enough to distinguish between singulars and plurals, or that you could try an asterisk wild-card. Where can I find this information, say beginner-level ninja search tips, rather than the super ninja search tips (which I've seen)?
Do an empty search, and there will be a link Advanced Search Tips that opens in-place (hence the lack of link here). I've copied the content of that help below. More help on advanced search in the Help Center's search-specific section.
tags [tag] exact "words here" author user:1234 user:me (yours) score score:3 (3+) score:0 (none) answers answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 views views:250 sections title:apples body:"apples oranges" url url:"*.example.com" favorites infavorites:mine infavorites:1234 status closed:yes duplicate:no migrated:no wiki:no deleted:no types is:question is:answer exclude -[tag] -apples
Search for unanswered questions that are not closed and has exactly one answer, i.e. has a single, unaccepted answer (from this post):
isanswered:no closed:no hasaccepted:no answers:1