How to inquire whether an invention is patented?

1. Carry out patent search: go to the patent office or search online by yourself;

2. The retrieval content includes the technical terms and related vocabulary to be retrieved;

3. Papers and public documents can also be searched on the Internet.

4. The general patent application can't appear in the online inquiry system in time, so whether a technology has applied for patent protection and been retrieved in time can't be 100% sure.