Fancy creating your own personal Wayback Machine (Archive.org)? WebSatchel is a free add-on for Chrome-based Web browsers. When you bookmark in your Web browser… “it creates a full copy of the webpage” on the WebSatchel Cloud service.
Users only get 1Gb storage for free, though. A test-save to PDF, of a fairly regular front-page of a robust blog, weighed in at 2.5Mb. So, at a guess, the free 1Gb might let you save around 350 pages. Pages are indexed in full-text (“every word on a page”) and made keyword-searchable for the user. Making it perhaps useful for a fairly small time-limited research project. I don’t know how easy it might be to “delete and start over” on a new project, or if your 1Gb can only be filled up once.
An additional search option, for searching stable sites as part of a small time-limited project, would be to create a Google CSE. A CSE would give you a wider and perhaps more serendipitous “catch”, and give your search Google’s leading relevancy-ranking. However, so far as I’m aware, there is no one-click bookmarking-like way to add a new site into a Google CSE. Perhaps there should be.