I'm not sure what you are looking for, but it sounds like you are after something really basic like a search engine like
www.google.com. The best way to improve your search results is to try and be more accurate. Also, if you are looking for a specific term, try putting your search in quotation marks: "search term".
I was going to say that
www.keyworddiscovery.com is what I think you are looking for, but are you a Internet Marketer looking for keywords, or just looking for information?