Amazon used to emply Udi Manber, who literally wrote the book on search. Yet it still doesn't offer basic search features every search engine has had for years, like using quotes for phrases, the plus sign to require a phrase to be present in the search result, or the minus sign to exclude keywords or phrases from search results. That's by design.

Amazon search is so useless that about half the time I use DuckDuckGo to search Amazon itself.