原文在這裏，Publication 901

China, People’s Republic of

An individual who is a resident of the People’s Republic of China and who is temporarily in the United States primarily to teach, lecture, or conduct research at a university or other accredited educational institution or scientific research institution is exempt from U.S. income tax on income for the teaching, lecturing, or research for a total of not more than 3 years.
This exemption does not apply to income from research carried on mainly for the private benefit of any person rather than in the public interest.