The impact factor, abbreviated as IF, is the data in the Journal Citation Report (JCR) produced by Thomson Reuters.
That is, the total number of cited papers published by a journal in the first two years of the reporting year (JCR year) divided by the total number of papers published by the journal in these two years. This is an internationally accepted periodical evaluation index.
To inquire about the influencing factors of Chinese journals, we can use the Comprehensive Citation Report of China Academic Journals (edited by Wan Jinkan, Science Press) jointly published by China Academic Journals (CD-ROM Edition) and China Scientific Literature Metrology and Evaluation Center.
The impact factors of SCI are generally published by Thomson Reuters in June each year. This is the most accurate official version, and other websites are for reference only, not 100% accurate.
The SCI periodical database under PubMed Chinese website can also query the impact factors and change curves of periodicals in recent ten years and the coverage area of periodicals.