For example, if you enter lung cancer and then press enter, a list of related articles will be shown as below. It shows that there are 91116 articles related to your key words.

If the result is too much for you to read, you can further search by putting more key words to narrower the field by "AND". For example, if I would like to know more about the relationship between lung cancer and tar, I can put "lung cancer AND tar" in the space provided. The list of article will be reduced. More information you provided, the smaller number of article will be shown.

Try to click the first article and the frame will be shown as below:

If you find some words that you don't understand, you can look for it in a on-line Medical Dictionary