熊猫搜索，熊猫搜书，聚合第三方文档、电子书导航网站和搜索引擎，快速检索网络资源。
This site lists free online computer science, engineering and programming books, textbooks and lecture notes, all of which are legally and freely available.
Zhelper V3 网址列表，额度充足 | Zlibrary 助手 V3 | Zhelper
Very well categorized. Equipped with advanced search engines.
快速切换搜索多个电子书网站资源
一个自由开放的在线古籍图书馆
电子书资源站
