The reason is:
1. stipulates that it shall be made public within 18 months from the date of application. If the applicant does not make an early disclosure request, it can only be made public within 18 months, and most of them may be made early. The application shall not be made public;
2. Some people accepted the application, but the first trial failed and needed to be corrected, and the applicant gave up;
Some people are not very clear about the concept of patent. They didn't apply for a patent and mistook some of their technologies for patents, but they didn't apply at all.
As for the retrieval method, you can query it on /sipo/zljs, and you can query it according to the application number, applicant, patent name or keywords in the abstract, and then select the needed patent after receiving it.