"Unified domestic serial number" is the abbreviation of "Unified domestic serial publication number", that is, "CN number", which is the code assigned to serial publications by the administrative department of press and publication. "International serial publication number" is the abbreviation of "international standard serial publication number", that is, "ISSN number", and most periodicals in China are equipped with "ISSN number".

In addition, just like newspapers, periodicals can be classified from different angles. There are as many classification results as there are angles, and too many angles are cumbersome. Generally classified from the following three angles.

Understanding the core journals is of great significance. As far as editors are concerned, they can learn from core journals. As far as readers are concerned, establishing the consciousness of core periodicals can clarify the value orientation and improve their reading level. For example, students majoring in language and literature should first read core journals such as China Language and Literature Review, instead of putting the cart before the horse.

As far as libraries are concerned, core periodicals are of course the first choice for subscription under the limited funds. As far as the scientific research management department is concerned, it can make statistical analysis of the papers published by units or individuals in core journals as an important indicator to measure their academic level.