That is a very broad question. It really depends on what you are looking for. Off the top of my head, I am thinking of possibly the British Medical Journal, New England Journal of Medicine, Canadian Medical Association Journal, and the Journal of the American Medical Association etc.
For websites, you could maybe try the Science Daily or Medgadget.
There is more information than you can handle out there and if you know where to look they should be readily accessible to you.