Online Textbooks
As you can see, this is China's standard textbooks.
All of these textbooks are originally from the offical website.
Remember that you can only use it for non-profit or educational purposes for the textbooks are copyrighted by the Chinese Ministry of Education and the National Textbook Committee.
If you know a bit about Node.js commands, you can also use my friend MrWillCom's downloader for quicker downloading.
*The textbooks listed in .gitignore are beyond the size limit, while you can download they on your own using the above methods.