The difference between the four districts is the difficulty of publishing papers and the different regions.

1, the difficulty of publishing papers is different: the first district is an internationally renowned academic journal, which is very difficult to publish; The second district is second only to the first district, and domestic authors have published more; The release of the three districts and four districts will be less difficult.

2. Different regions: The first region refers to the provinces with relatively strong educational and economic resources, which are concentrated in the eastern region; The second district refers to the provinces with relatively weak education and economic resources, which are concentrated in the western region.