The first, second, third and fourth zones of sci refer to the division of SCI papers, and there are two types of SCI journals with wide influence: one is the division made by Thomson Reuters (called Thomson Reuters division for short); The second is the division made by the National Science Library of China Academy of Sciences (referred to as the division of Chinese Academy of Sciences). Thomson Reuters Branch, Thomson Reuters publishes a journal citation report (JCR) every year. JCR has counted more than 86,000 SCI journals such as Impact Factor. JCR divides journals into 176 different disciplines. According to the impact factors of journals, each subject classification is divided into four areas on average: Q 1, Q2, Q3 and Q4. In the classification of various disciplines, the top 25% (including 25%) journals with impact factors are divided into Q 1 region, the top 25% ~ 50% (including 50%) journals are in Q2 region, and the top 50% ~ 75% (including 75%) journals of Thomson Reuters are divided into four parts on average. China Academy of Sciences is divided into six categories: mathematics, physics, chemistry, biology, earth science, astronomy, engineering technology, medicine, environmental science, agriculture and forestry science, social science, management science and comprehensive periodicals. Then, the journal 13 is divided into four grades, that is, four districts. According to the impact factors of various journals, the top 5% is 1, 6% ~ 20% is 2, 2 1% ~ 50% is 3, and the rest is 4. In the branch of Chinese Academy of Sciences, there are few magazines in 1 and 2 areas, and the quality of the magazines is relatively high, which are basically the top journals in this field.

Legal basis:

1. Notice issued by the Ministry of Education and the Ministry of Science and Technology. Accurately understand SCI papers and related indicators. SCI (Scientific Citation Index) is a widely used index system for scientific and technological documents at home and abroad. SCI papers are published in SCI journals, and the related indicators include the number of papers, the number of cited papers, highly cited papers, impact factors, ESI (Basic Scientific Indicators Database) ranking and so on. These are not the direct basis for evaluating academic level and innovation contribution.