https://arxiv.org/ :Arxiv
1, China HowNet (journals, dissertations)
2, Relative Information Chinese scientific and technical journals database (Papers)
3, Wanfang digital resources system (theses, conference papers, foreign literature)
4, read show Scholar
5, Superstar Digital Library (e-books, lectures, read show Scholar)
http://www.naturechina.com/subscribe natural
https://www.sciencemag.org/ Science