sci-hub

外文期刊文章基本检索

思谋学术是提升科研效率的常用工具，自动检测和更新可访问的Google学术镜像网址,并提供学术资源导航与文献免费下载通道。

万方数据知识服务平台-中外学术论文、中外标准、中外专利、科技成果、政策法规等科技文献的在线服务平台。

More than 340 mio. scientific documents from more than 11.000 content providers. BASE is one of the world's most voluminous search engines for academic web resources.

iData-用户中心

Open Access Library (www.oalib.com) is an academic search engine and publisher. You can download research papers for free and submit your paper to it. It is a shared academic database.