Does the SE search engine search the term among comments and answers, or only questions? For example I want to find a comment and I remember some words of it, is there a way to find it?
You can try to find it by creating a query on data.stackexchange.com. For example: http://data.stackexchange.com/stackoverflow/query/62213/search-comments
There's not a way to search for what you're after yet. The search engine doesn't index comments or wikis...at this time.
Check out the (hidden) search help page
is:answer apples oranges
will search for "apples" or "oranges" in answers only.
I don't think there's one for comments.