1. Entrusted to China National Intellectual Property Administration Patent Information Center or Patent Office.
2. Search online by yourself.
3. Search online in the document library of China National Intellectual Property Administration Patent Office.
You don't have to go through a patent agency. Most agencies don't provide international patent search.
It is normal to search for miscellaneous things, and the free database we use will be missed because it is not further processed. It is recommended to use the paid database for retrieval. Please consult China National Intellectual Property Administration Patent Information Center for details.