How do I block specific web sites?

Can I filter & block certain Web sites from ever appearing in search results, and how?

• There doesn't seem to be any "browser" subcategory so "general internet" was the closest I could find. What I want to do is to NOT keep seing search result that have been proven to be unreliable sites; or sites with incompetant or corrupt features . . . such as (say, those Q&A sites with) inept and corrupt/dishonest monitoring and supervision. These are often sites like those that mimic and plagiarize the names and content of reputable sites such as wikipedia--you may have seen them. I have considered that some kind of parental control might work but have never used that browser feature; and I want to make sure that distasteful sites do not even appear in search results. Thank you.

• Answer:

  Its not a great method, but you can put one or more websites in your searches and subtract them. Something like pool table -linkfarm.com -spamcrap.org Filters of the parental control kind won't work because they block sites, not search results. I found this for Firefox: https://addons.mozilla.org/en-US/firefox/addon/12305/