The difference between core journals and 397 journals.

1. The general rule is that the periodicals in the second district are easier than those in the first district. 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.

2. Therefore, the first area, the second area and the third area of SCI papers refer to the classification of journals in SCI database at different levels according to factors such as impact factors and cited amount, in which the journals in the first area represent the high-level journals with the highest influence, and the journals in the third area are low-level journals.

3. Zone123: The division table of China Academy of Sciences selects academic influence as the division method, and arranges all journals in various disciplines in descending order according to academic influence (3-year average IF), and divides them into four zones in turn, so that the total influence of journals in each zone is the same.