How to inquire whether foreign drugs are protected by patents in China?

Patent protection is regional, and the laws of a country only protect its application, but if it enters another country from the international market through a similar PCT, it generally has an international stage. If you may be a new technology in your own country, but you may not be novel or creative in other countries, then you may be rejected on the international stage. Without international review, patents applied only in one's own country are likely to be infringed in other countries, but production will not be banned because there is no patent in that country.