CNKI (China National Knowledge Infrastructure) is a key national information construction project. In 1999, CNKI started to develop online databases. CNKI has become the largest and mostly-used academic online library in China. In January 2013, CNKI was designated as the second agent of DOI in mainland China by International DOI Foundation, and the first one was Institute of Scientific and Technical Information of China.
Google Scholar provides a simple way to broadly search for scholarly literature. From one place, you can search across many disciplines and sources: articles, theses, books, abstracts and court opinions, from academic publishers, professional societies, online repositories, universities and other web sites. Google Scholar helps you find relevant work across the world of scholarly research.