Or let's put it this way: Generally, SCI papers are divided into four areas, the first area is the top international journals, the second area is the second, and the third and fourth areas are general SCI journals.
American Science Citation Index (SCI) was founded by institute for scientific information in Philadelphia in 1957. It is a citation database established and published by institute for scientific information in the United States at 196 1. SCI (Science Citation Index), EI (Engineering Index) and ISTP (Science and Technology Conference Index) are three world-famous retrieval systems for scientific documents, which are internationally recognized as the main retrieval tools for scientific statistics and scientific evaluation, among which SCI is the most important. )。
SCI has two partition rules: JCR partition and CAS partition.
According to the impact factor (IF value), all journals of a certain discipline are arranged in descending order according to the impact factor of the previous year, and then divided into four parts (each accounting for 25%), namely Q 1, Q2, Q3 and Q4.
The zoning method of China Academy of Sciences is as follows: the first area journals: the top 5% of the three-year average impact factor of various journals, the second area journals: the top 6% ~ 20%, the third area journals: the top 2 1% ~ 50%, and the fourth area journals: the last 5 1% ~ 100%.
affect
Scientific citation index is based on Bradford's literature dispersion theory and E. Garfield's citation analysis theory. It evaluates and studies academic journals and scientific research achievements in many aspects by counting the cited frequency of papers, so as to judge the performance of scientific research output of a country or region, scientific research units and individuals and reflect its international academic level.
Scientific citation index is one of the most famous retrieval publications in the world, and it is also an important tool of bibliometrics and scientometrics. Through the citation retrieval function, you can find the early, then and recent academic documents of related research topics, and at the same time get the abstracts of papers; You can see the records of cited references, the cited situation and the records of related documents.
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.
The periodicals collected by SCI mainly involve basic scientific research fields such as mathematics, science, chemistry, agriculture, forestry, medicine and biology. The selected journals come from more than 40 countries with more than 50 languages, among which the main countries are the United States, Britain, the Netherlands, Germany, Russia, France, Japan and Canada, and some China (including Hong Kong, Macao and Taiwan) journals are also included.
References:
Baidu encyclopedia? Index of scientific citations