How You Ask
We've already established that where you look influences the outcome of your search. So does how you ask.
Suppose you are asked to write a paper in support of this assertion:
The proliferation of fast food has led to the national problem of obesity.
So what's the big deal? You just get in there and type it in the search box, right? WRONG!!!!! There are many irrelevant words in this search statement. If you typed in all the words, you would find nothing. A cardinal rule of searching is: The more you key in, the less you get back.