You won't be able to succeed unless you have a guangxi with a local professor. Trust me.

Show up at offices, meet people face to face.

Having followed this thread over the past couple of days, a few new thoughts spring to mind.
Usually in China people will not say no, as they do not want to be the bringer of bad news. They just don't get back to you. Sound familiar?
As for annoying people, I think that will get you nowhere, and could well put up barriers. You might be able to corner someone face to face. They may even say yes, and then they will do nothing and become un-contactable.
Are you doing undergrad, masters, or doctoral/post-doc research? If it is the first two, I doubt you would get a response.
Someone also mentioned 'guanxi', in China it is not what you know but who you know.
Remember, just because you really want to do something, and that it may even be of value, does not mean that others are obliged to help in any way whatsoever, and altruism is not common.
Anyone who might be in a position to help you will also consider that anything that might shine a light into a dark corner may cause them, or their bosses, some loss of face and they will not want to get involved, unless they are ordered to from above.
If you really want to do research on Chinese subjects, you will probably need to work with secondary data, if you can get access to it. This way you can work on your own.

Well, I think you can probably arrange to collect primary data as well, in classrooms and schools - at least some participant-observation (access through school interest in having English speakers chat with kids, and I know you can find teachers who will talk, and people in education departments at, say, Yunnan Shida or elsewhere) - but if you've volunteered as a teacher you know that - anyway class observation - but it might be a bit tricky to set it up.
Again, I think you should be here on any visa and see how you can begin, perhaps informally, and go from there.

.

thanks again for the answers!
so, i contacted every University in Yunnan - no reply
i contacted bureaus and institutions (like departments of the ministry of education, confucius institute) - no reply
i contacted a person from beijing university, he gave me the mail address of a professor in yunnan - no reply
i have a friend who works at the pu'er college, she did everything she can, talked to the headmaster and so on, they can´t help me because of the strict examination system - no chance

so i still didn´t give up and i definitely think it´s easier to get in contact face to face than via mail, and maybe thats why i have to figure it out with a tourist visa, but still not the best option.

and i saw the last post which is deleted, it´s about ethics and morality. and I definitely know all the ethics I have to follow (as a researcher I have to know them). And I know that doing research without permission is the worst thing I can do, and I wouldn´t just go to the school and tell them I want to oberserve but not telling them why I want to do it. So yes, obviously I want to have the permissions and I need to have the permissions so that I can do research.

Good luck kaddi

@kaddi
As a foreigner, you are trying to come to Yunnan hoping the university will use some of its allocated funding to pay for you over a local student.

You will most probably take your 1-2 year of funding and return home along with your knowledge. A local student will most probably continue to live here and contribute to the domestic infrastructure.

Unless you're exceptionally famous, graduate from an exceptionally famous university, or have an exceptionally famous faculty member directly refer you to one of his/her colleagues at PuEr Univ - I sincerely doubt you'll have any success.

If you were to enroll as a paying student - that's a completely different story - but don't expect the local or national government to finance you.

FYI - a direct introduction means a person to person phone call to their mobile...land lines and email are rarely answered.

@michael2015 i Never Said in any of my words that I expect that the university pays for my stay. And I wouldn’t dare to expect that :)

I think he means tuition fees. You will have to pay them.