I recently came across a quirk that can help increase precision. It's a side effect of this suggestion:
The query doesn't necessarily need to be "more specific". Introducing any Boolean operator (AND, OR etc) changes the matching mode app search uses. Without Boolean operators, search terms are chopped into parts ("ngrams") so that dress effectively searches for dress OR dre OR ess. This form of fuzzy matching should rank dress or dresses highest but will also match words like mattress.
As soon as you introduce a Boolean operator of any kind app-search switches mode and searches for exact words only, not parts of words. The example searches below would only match documents with the word dress and not mattress:
dress AND dress
dress OR dress
dress NOT wordThatDoesNotExist
dress OR wordThatDoesNotExist
"dress"