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.