Search engines are about the most useful kind of web page on the internet, without them the internet would be almost unusable for many people. "Surfing" would be a very different sport altogether.
Some are specifically designed to be used for and within certain subject areas but the problem with most of them is that the results of any given search are so varied that without very careful selection of the keywords to input, one is most unlikely to find exactly what one is looking for.
This goes triple for serious or even semi-serious academic research. One technique I've found for scientific searches gets around the vagueness very neatly:
Learn Latin. Ok, this is a tall order, so maybe better advice would be to look up whatever you're looking for in a Latin dictionary. Anything to do with the sciences (and a bunch of other subjects) is chock full of Latin terminology.
For example, do a search on "red foxes" in Google or Altavista. I'll bet you anything that the first results you get are all about some high school (American) football/hockey/basketball team. You will also notice that some red foxes links won't refer to anything more than red headed cheerleaders doing dubious things with vegetables.
(Oi! Come back here! Don't look at that, it's rude.)
Ok, now that you're done with them (feel better big fella? now wash your hands...) back to the subject in hand. As it were.
Now pump (goodness me) in the words "Vulpes Fulva". I know, I know, that sounds even worse, maybe a better example would have been less distracting. But my point is that you'll get nothing but results on the "real" red fox.
It's just a way to avoid the porn (pornographers rarely know any Latin) and other irrelevancies in your searching and it works beautifully.