Ebook
you can check the book whether has a electronic version through worldcat.
For Chinese book, you can check by Duxiu.
Google Book
The content of it may be same with https://babel.hathitrust.org/, a large-scale collaborative repository of digital content from research libraries and is administered by the University of Michigan (Wikipedia).
Collections: old and scanned book
If the book is “read for free”, you can scrape the images by the tool. If it’s “preview”, you may be able to download the whole book by switching different country proxies.
Tools: Google Books Downloader
chaoxing
For the old version of ssreader, the PDG file will be downloaded and be encrypted locally. We can capture the http packet and ssreader and save the body of response. Then convert the PDG file to pdf by PDG2PIC.
Standard
Chinese Standard
All Chinese standards can be found at https://www.spc.org.cn/. And it collaborates with CNKI, to provide some content to the institudes.
You will download pdf file and need to decrypt it to share.
Tools: https://github.com/301Moved/ScienceDecrypting
