The Living Thing / Notebooks :

Flashcards

Spaced repetition systems

More on the theory and background has been written by others.

Here are some practical notes for my own personal usage.

If you need to build flash card to cover your own research area, there are two contenders, Anki and Mnemosyne. I use the former because it has the convenient features of testing your flashcards on the iphone, but they are both open-source-ish.