Enter official website, a database of WebofScience, enter the documents you want to query in the search bar, and click the corresponding title in the search results. After clicking enter, you can see the most basic literature information such as author, abstract, publishing house, subject category, etc. Some websites will also directly display the "Tibet entry number", that is, the index number.

However, for articles that do not display the index number, you can choose to enter the paper description details page, select "Output all records", and then select "Save as HTML format". Finally, open the HTML file saved in the computer, slide down to the last page, and you can see the contents written with the word "ISI". A string of numbers written after ISI is the index of the paper.