STD Clinic that will check you out for all possible STDs. Expect to pay about 250rmb to check everything except HPV and Herpes, which will cost you an extra 400rmb or so. It's a Chinese public hospital, so the prices are much lower than at a Western place, though you may have to wait about an hour to see a doctor. For a full account of the place, see this SmSh article on the place.