Well there's still the search box at the very top of all pages. In between "Quick Links" and "Articles." Every thread comes with a "Search this thread" at the top. And you can still search each forum, but I don't remember where the box is at without checking, brb!
Alright, I'm back. Just click the "Search this forum" at the top of every forums thread listing. There did used to be a box down though, your right. They should bring that back