In the past 50 years, SCI database has developed continuously, and has become the most important large-scale database in the contemporary world, ranking first among the six famous international retrieval systems.
In addition, with ISI, Social Science Citation Index (SSCI) and Art and Humanities Citation Index (A & amp； HCI). It is not only an important retrieval reference book, but also an important basis for evaluating scientific research achievements.
It has become the most authoritative and important evaluation system of basic research and applied basic research achievements in the world. It is one of the important indicators to evaluate the academic level of a country, a scientific research institution, an institution of higher learning, a journal and even a researcher.
No matter whether it is the first district of jcr Division or the first district of Chinese Academy of Sciences, as long as it is a district periodical, it is internationally renowned.
The second district periodicals are second only to the first district periodicals, and the domestic authors of the second district periodicals publish more. At present, some domestic standards explicitly require the publication of two or more periodicals, so two-zone periodicals are the first choice for many domestic authors. The publication of periodicals in the second district is slightly less difficult, but it depends on specific disciplines and periodicals.
It will be less difficult to publish periodicals in three districts and four districts, but there are some disputes in China. It is precisely because of the above rigid requirements that some units and universities do not recognize publications below the second district.