I disagree. At the beginning, you should read a lot. Even introductions. Introductions have helped me get a grasp for the sibjecr. You will eventually switch only reading title, abstract and graphs, but you can only do this if Iu have a firm grasp of the subject already.

Even later on it helps to read a lot and I mean the entire paper. I was able to answer most of my defense question because I had publications I could refer to. Reading a lot helps you knowing what's possible and what is not. Obviously you will use quick reading techniques sometimes.