I have used a database for some time and then the link disappears from the database page. Why ?

Release time:2021-05-28119

(1) Some databases listed on the library website are databases on trial and the library has not yet subscribed to them. The expiring date is indicated for each trial database on its introduction page. You are welcome to tell us your opinion on a trial database (find contact information of the responsible librarian on database introduction page), because your suggestions are important to us.

(2) The library may stop the subscription of a database if it is rarely accessed.