I've added a new search box at the top of the page, which uses Google to search the site, rather than the built in search engine which isn't great for certain kinds of searches. You can still access the old version by clicking on Advanced Search.
The first few results of each search are adverts, but it's obvious what they are so you can just skip past them.
The first few results of each search are adverts, but it's obvious what they are so you can just skip past them.