The library of Shahe Campus in Changping can be accessed, but the books are not complete. The card swiping at the entrance of Cai Zhong Headquarters Library in Haidian District is not very strict. You can sneak in when the security guard is not looking, but you can't borrow books. Besides, there is a bookstore next to the headquarters called Siyuan Cai Zhong Bookstore, where you can buy it.

PS: I'm a lottery winner.