There may be many reasons why you can't find a health certificate online. First of all, it may be because your medical examination results are unqualified, which leads to your health certificate not being taken out or cancelled. Secondly, if you have just finished the physical examination, it may be because the physical examination results have not been entered into the computer system corresponding to the health certificate, and it will take some time to find out. In addition, if you enter the wrong query information, such as name, ID number, etc. , inconsistent with the health certificate registration information, will also lead to no query results. Therefore, it is recommended to check your personal information carefully and wait for a while before trying to inquire.