What are the negative effects of the "closed door" policy?

Negative effects: China is isolated from the world, which seriously hinders the budding development of capitalism. It derailed China and the world, and slowly fell behind the world. Culturally, economically and scientifically, it is impossible to connect with the world, and it is difficult to develop all kinds of advanced technological ideas, showing the empire dusk phenomenon as a whole. It is the root cause of China's backwardness and beatings in modern times. Reducing the chances of contact with the outside world has hindered the country's economic development, completely lost the initiative in foreign trade, hindered scientific and technological cultural exchanges with foreign countries, and even hindered the development of productive forces and social progress, limiting the development of foreign trade and navigation.

hope to adopt.