A very good library understands the network. Excellent libraries know the Internet;

1. Although the library charges are extremely expensive, it is very cheap.

2. The account of the excellent library needs to be recharged in Taobao. The current price is one month in 4.5 yuan 120 yuan. HowNet and Wanfang interface websites all have them. You can buy an account together in a dormitory, and four years is very cost-effective. Therefore, a very good library knowledge network.