Nine popular websites for accessing literature

1、Web of science https://www.webofscience.com/wos/woscc/basic-search 2、Ei Engineering https://www.engineeringvillage.com 3、IEEE xplore https://ieeexplore.ieee.org/Xplore/home.jsp 4、Elsevier https://www.sciencedirect.com/ 5、SrpingLink https://link.springer.com/ 6、Nature https://www.nature.com/ 7、PNAS https://www.pnas.org/ 8、Socopus https://www.scopus.com 9、Google Scholar https://scholar.google.com/