During the Cultural Revolution (1966–1976), scientific work came to a halt in China. Universities closed, primary and secondary school education shut down, and intellectuals (including scientists and engineers) were sent to the countryside or to factories to work. The effects of the Cultural Revolution are reflected in China's output of scientific literature. In 1973, for example, only one Chinese paper appeared in any of the world's 2300 most central journals covered by theScience Citation Index. After restrictive policies were loosened, however, scientific papers grew exponentially. By 1982, only six years after the Cultural Revolution ended, Chinese scientists produced 932 papers. This exponential growth of papers leveled off at this point and the number of papers appearing in the core 2300 journal stood at approximately 1000 in 1983 and 1984.