Ainosco 是科探索 
https://www.ainoscosearch.com/
Full text book search engine for books published in Taiwan, Hong Kong and mainland China
Ariti E-Books 华艺中文电子书 https://www.airitibooks.com
It provides access to Chinese ebooks primarily published in Taiwan, Hong Kong and Macau. It covers subjects such as philosophy, religion, natural sciences, applied science, social sciences, history, geography, language and linguistics, and literature and arts.
China Digital Library (Apabi E-books) 中华电子书苑 http://www.apabi.com/uc/?pid=foreign.search&db=dlib&dt=EBook&dc=1.6&hdc=1&cult=CN
Duxiu 读秀 http://www.duxiu.com/
More than 1.4 million full-text books
Currently available -- full-text searches, tables of content, and first 17 pages
Browse and forward purchase suggestions to Xi Chen, xichen031@ucsd.edu
Pishu 皮書 China Economy, Public Policy, and Security Database http://dlib.eastview.com/browse/books/1610?searchLink=%2Fsearch%2Fsimple&enc=zhc
These analytical reports published by the prestigious Social Sciences Academic Press, are intended to guide policymaking in the PRC.
