How do I get a chinese visa?

Dear Sir/Madam,
I'm a professor at a reputed Law college at Kathmandu. I want o visit some universities and colleges in order to build student exchange programs and for joint research. I wrote to many universities but all the e-mails got bounced and I didn't get any invitation. I want to visit Fudan University Shanghai. Can I apply for visa without invitation letter? what other documents (other than filled up application form) I need?