A unique search tool, helping you to find free academic articles and books

Baidu Scholar aims to become the biggest, most comprehensive research platform in China.

Semantic Scholar helps researchers find better academic publications faster

A service to help the academic community find academic content, researchers, and more.

Online rental service for scientific, technical and medical research.

Google's mission is to organize the world's information and make it universally accessible and useful.

Access to major journals in the biomedical and related social sciences fields.

Search metadata records for journal articles, field-specific, for software.

Article recommendation and literature discovery service in biology and medicine.

Mendeley is a desktop and web program produced by Elsevier for managing and sharing research papers, discovering research data and collaborating online.