Patent documents can be downloaded for free, and the principle can be referred to. Go to the website of China Intellectual Property Office to find the download.
If you know a little English, go to Taobao, the website of www.scirp.org. All domestic and foreign literature about it can be downloaded for free. You can enter relevant online magazines from the columns of chemistry, engineering and materials. , or you can use keywords to find documents directly.
You register a user name in some large-scale chemical and chemical professional forums, find the document address, go to the forum for help, and someone will upload it to you in half a day. For example, China Chemical Forum, Haichuan Chemical Forum, Vanke Chemical Forum, Woodworm Forum, Garden Reading Forum, Instrument Information Network Forum, etc.
In fact, why go further and further? Baidu can ask for help in "Know".