Are the papers in the doi system regular?

Yes, doi paper system was officially released as an ISO international standard in 20 12, and it has become a global standard for identifying and linking digital resources. The papers in it cover most regions and countries, and they are all official papers. In the academic field, doi is usually used to identify digital resources such as journal papers, conference papers, book chapters, patents, technical reports, etc. Each paper will be assigned a unique doi number after publication.