Volume is the time classification above the cycle, volume is the number sorted by year since publication, and cycle is the number sorted by time this year. In order to sort the periodicals for easy query, domestic periodicals are divided into volumes and issues according to time. For example, the papers published in 2065438+March 2007 are sorted by volume number and issue number, that is, the third issue of Volume 23. Domestic regulations on periodical volume number and issue number are relatively uniform. For example (Volume 55, Issue 02): If you want to find an English periodical, you must know its serial number. The number of English periodicals is also expressed by volume number and issue number, and some will be expressed by page number. The marking method of volume number and issue number of English periodicals is different from that of domestic periodicals. You can see the marked volume number and issue number in the lower corner of the English test paper. Every English periodical has different marking methods. Some periodicals only have volume numbers and no issue numbers, while domestic periodicals have both volume numbers and issue numbers. Papers that have been successfully submitted but not officially published have doi numbers, which can also be found in the database, without volume numbers and page numbers. There is no uniform standard for the volume number and issue number of English periodicals. Periodicals can be classified into informal periodicals and formal periodicals. Informal periodical refers to the periodical that is approved by the administrative department to receive "internal approval confirmation" as an internal communication (internal communication only, not public distribution), but it is also a legal periodical, and all official periodicals have gone through the process of informal periodical. Official periodicals shall be examined and approved by the Press and Publication Administration and the State Science and Technology Commission within the agreed number and incorporated into the "unified domestic serial number". The application for running a journal is relatively strict, which requires a certain publishing strength. Official periodicals have an independent publishing policy.