1, ipa.gov.cn/sipopublicsearch/portal/uiIndex.shtml. China National Intellectual Property Administration patent retrieval analysis network.
2. Free commercial patent search website:/; /; /search/
3. Paid commercial patent search websites:/; /
It should be noted that because the utility model and design patents were published only after authorization, there is a blind spot in the retrieval results (the time between the application date and the authorization announcement date), so any retrieval method can not be completely retrieved.