Optical Valley Bookstore also has official invoices.
Chongwen Bookstore can also issue official invoices.
In addition, the book search function you mentioned, the larger bookstores have computer search books: Vu Thang Road Xinhua Bookstore, Guanggu Bookstore and Chongwen Bookstore. You can search the names of these bookstores online, and you should be able to find them ~ ~ but it seems that the online bookstores of Optics Valley Bookstore can't be found. I didn't find it the day before yesterday, but I can find it in Guanggu Bookstore ~ ~ ~