You could try HistoryHound.app
HistoryHound lets you do a fast keyword search on the entire content of all web pages and RSS feeds you’ve visited recently, plus all those that you’ve bookmarked. It’s a “personal web search.” Just type in a few keywords and HistoryHound gives you a list of pages you’ve viewed recently, ranked by relevance.
If you sync your iPhone’s and Mac’s Safari via iCloud then HistoryHound will also include what you’ve visited on the iPhone.
And it’s possible to search with (some) of the Google search operators, e.g. site:https://discourse.devontechnologies.com returns everything for the given time range.