My friend, you are talking about provincial and national periodicals. The CN serial number actually refers to the domestic serial number, and ISSN is the international serial number. If you want to evaluate a professional title, all regular journals have a complete double serial number and a postal code, because they are publicly issued all over the country, such as Medical Information, Required Reading for Health, China Practical Medicine and Seeking Medical Advice. These are all good. Don't worry too much, it's easy to be cheated. For places where the price is surprisingly low and the publishing speed is surprisingly fast, it is recommended to stay away, because the periodical publishing cycle is only one month at the earliest, and it is not realistic if it is faster, and it is even more incredible if you can promise anything. It was published on Qiuzhi. com before, but now the book has been received, and it feels good. At first, I was dazzled by the information on the Internet. Pick me.