The core of Peking University is the academic definition of a certain kind of periodical, usually called China Core, which is collected by Peking University Library and updated every four years. The core periodicals refer to the catalogue selected by China Institute of Science and Technology Information, which is updated 1 year. Generally speaking, the core of Peking University is higher than the core level, and some periodicals are included in these two catalogues at the same time, commonly known as dual core.

The core of Peking University is the periodical inclusion proposal formulated and published by Peking University Library, which is used to guide the libraries in the Chinese world to collect and subscribe periodicals.

The object of its grading evaluation is mainly Chinese periodicals, and the object of its service is libraries. At the same time, the core collection of Peking University is also used as a reference evaluation index by many universities or project evaluation institutions.

Brief introduction of core journals:

Core journals are the main journals of a certain discipline. Generally speaking, it refers to a professional periodical with a large amount of professional information and high quality, which can represent the development level of professional disciplines and is valued by readers of this discipline.

Relevant experts have found that the actual distribution of literature information sources has the effect of core journals, that is, a large number of scientific papers in a professional world are concentrated in a few scientific journals.

This phenomenon can be seen in many fields, for example, from the study of the world literature of physics in France's Signal Bulletin, it is found that 90% of abstract items are only taken from 30% of all journals, and chemical abstracts can extract 75% of all abstract items from 9% of journals.