What do you think are the reasons for the stagnation of China's scientific and technological development in the late Ming and Qing dynasties?

After the middle of the Ming Dynasty, the natural economy dominated and the feudal system became increasingly corrupt. The rulers strengthened the state apparatus to effectively rule the country, at the same time, in the ideological and cultural implementation of harsh authoritarian policies, completely stifled the vitality of the Chinese people's thinking. The Qing Dynasty's closed-door policy, so that Chinese culture can not communicate with the world, into a stagnant point.