Where can I buy core technology patents?

Patents that have not been applied in China are not protected in China, and imitation production in China is not infringing. If it is a patented technology, you can get its technology by querying the patent. If it's not in the patent, it's a technical secret, and I'm afraid it's hard to get it from other sources. If it is a product patent, it can be obtained through disassembly analysis.