Zukmo and historious do let you search the entire content of the page.

However, unlike historious, Zukmo does a lot of additional stuff with the pages that you add to Zukmo. It automatically categorizes them. It also provides an uncluttered view (Easy Reader) similar to Safari Reader and Instapaper Text View. This will come in handy when you view it on mobile devices (we are currently working on apps for the iPhone, iPad and Android). With Zukmo, you can also share on Twitter, Facebook and via email right when you add the page to Zukmo.

Also, other than bookmarks, we will be adding the ability to add your Twitter and Facebook streams as well as RSS feeds into Zukmo.