I have spent 5.5 years in China, Phd and postdoctoral from China, now I would like to apply for

Shahid, if you want to apply for tourist visa, you may need to join a tour group organized by a travel agency. However, I noticed that you posted this question on the page of China consulate in LA, so do you plan to apply from US? If so, it's possible that you are able to apply for an individual tourist visa. Just have a try.