SCI (Science Citation Index), EI (Engineering Index), CPCI (Conference Proceedings Citation Index, formerly known as ISTP--Index to Scientific & Technical Proceedings), are three famous scientific and technological literature retrieval systems in the world, which are internationally recognized as main retrieval tools for scientific statistics and scientific evaluation.

Since 2009, EI collections can be divided into periodical retrieval and conference retrieval. That is, JA-Journal Article type and CA-Conference Article type.
  Generally speaking, JA-Journal Article type grades higher CA-Conference Article type in most professional title systems.

Regular issues are regularly published weekly/monthly/quarterly/yearly, etc.
  A supplementary issue is an additional supplement based on academic conferences or other special topics, in addition to regular issue.
  A special issue is specially published for a certain academic field, which can be either regular or supplementary issue.

"ISSN" is the International Standard Serial Number. It is a unique identification code assigned to serial publications of various content types and carrier types (such as newspapers, periodicals, yearbooks, etc.).
    ISBN is the International Standard Book Number; it is the code of international books or independent publications (except periodical). Publishers can clearly identify all non-periodical books by ISBN.
    CN number is a unified domestic issue number in China.
    In short, ISSN is an internationally recognized journal number, CN is a domestic recognized journal number in China, and ISBN is an internationally recognized book number.

Open access, abbreviation OA, is a kind of action taken by the international academic, publishing and intelligence circles to promote the free dissemination of scientific research achievements through the Internet.
   Take publishing academic papers as an example. Traditional publishing: the author puts the paper into a journal. After the journal is published, the copyright is generally owned by the journal. Other people need to pay for your paper to see it.
   The biggest difference in Open access is that the people who pay have changed, and it's the authors who pay. When an author publishes a paper, he pays the journal or the publishing house. After that, people who want to see your paper don't need to pay any more. They can view the full text of your paper anywhere on the Internet.
    This kind of journal generally adopts the operation pattern that the author pays for publishing, the readers get free and unlimited use, and the copyright of the paper is reserved by the author.
   In terms of paper quality control, OA journals are similar to traditional journals and adopt strict peer-review system.