There are many ways to check this. You can directly check the EI database, enter the English of your paper, and click Search. If all the words can be matched, it means that the paper EI has been searched. If not, it means that EI has not been entered (note: there can be no spelling mistakes in English, so check carefully before searching). But generally, if this EI database goes in, you need to log in. You can search "EI Academic Conference Center" in Baidu, which has an EI search portal. I hope I can help you.