谷歌学术/谷歌镜像

对70多个国家的61个数据库及门户进行跨语言搜索。WorldWideScience.org is a global science gateway accelerating scientific discovery and progress through a multilateral partnership to enable federated searching of national and international scientific databases.

清华大学的一站式的文献资源检索系统

为科学、技术和医学文献提供在线搜索引擎和租赁服务。DeepDyve is the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.

国家哲学社会科学文献中心

酷科研，更好的科研大数据平台。酷科研是一个科研大数据平台，聚合了大量科研资讯，提供了期刊文献，国自然，知网等科研相关等数据检索、分析功能，提供文献全文下载，期刊影响因子趋势查看，期刊JCR分区，中科院分区，Sci-hub最新地址等

免费提供生物医学方面的论文搜寻以及摘要的数据库。PubMed® comprises more than 34 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full text content from PubMed Central and publisher web sites.