Tried the Full Text Search:

Yahoo is a 404 error that wants fixing.

Google includes ads if one presses the return key.  No ads if one clicks the [Google Search] button.  Probably not in your control but a short mention next to Google might be in order.

DuckDuckGo gives the same results with the return key and with the [DuckDuckGoSearch] button.

Other than the ads bit, both Google & DuckDuckGogave good text search results.