Most of the time, as the study or work needs, we need to publish some papers. When writing papers, we also need to refer to some of the previous experience for reference, so we need to master the method of looking for literature materials, and then refine their own views according to the literature. Here xiaobian to share some common foreign free paper search sites.

　　1. OALib free paper search engine

　　Website: http://www.calib.com

　　OALib is a website with more than 420W academic papers, covering mathematics, physics, chemistry, humanities, biology, materials, medicine and humanities, all of which are free to download; One of its features is the function of page snapshot support, not out of the station can directly browse the article title, author, keywords, as well as abstract and other basic information, greatly shorten the time cost, is a more efficient paper search website.

　　2. BaseSearch is an academic search engine based in Bielefeld, Germany

　　Website: https://www.base-search.net/

　　It is a multidisciplinary academic search engine developed by the renowned Bielefeld University library in Germany, providing integrated search services for global heterogeneous academic resources. BaseSearch integrates the library catalogue of the University Library of Bielefeld in Germany with data from about 160 open sources (over 2 million documents).

　　3.BioMed Central Life Sciences Online Journal

　　Website: https://www.biomedcentral.com/

　　BMC has a developing portfolio of approximately 300 peer-reviewed journals that share findings in the fields of science, technology, engineering and medical research. BMC has now expanded from biomedical to physical sciences, mathematics and engineering disciplines, offering a wider range of disciplines on a single open access platform.

　　Highwire, Stanford Academic Literature electronic journal

　　Website: https://www.highwirepress.com/

　　Highwire claims to be one of the world's largest publishers of free full-text academic literature. The website includes 882 kinds of electronic journals, including life science, medicine, physics and social science, with a total of 2.82 million articles.

　　5. IntechOpen Free science and technology literature

　　Website: https://www.intechopen.com/

　　Intechopen provides free scientific literature covering biotechnology, computer and information science, earth sciences, electrical and electronic engineering, materials science, medicine, technology and other scientific fields.