Highlighting text in PDF document

I am a surgeon and subscribe to lot of medical journals which are now increasingly made available for downloading in PDF format. I am used to highlighting the important text in an article with an ordinary hi-lighter pen to make it easy when I need to go back to that article.

Is there a way one can highlight the text in a PDF document the way one can highlight it on a paper? Will professional versions of Acrobat solve my problem?

Sanjay Ghotkar