China HowNet: initiated by Tsinghua University and Tsinghua Tongfang, it was established in June, 1999. Navigation covers natural science, engineering technology, agriculture, philosophy, medicine, humanities and social sciences. Readers can directly browse the basic information of periodicals and find periodical articles on schedule.

Wanfang Database: Wanfang Database is a large-scale network database developed by Wan Fang Data Company, covering periodicals, conference minutes, papers, academic achievements and academic conference papers; It is also a professional academic database in China, and enjoys the same reputation as China HowNet.

VIP Information Network: VIP Information is a large-scale specialized data company under the Southwest Information Center of the Ministry of Science and Technology. China is the founder of periodical database construction, and has become the largest comprehensive literature database in China.

Foreign paper retrieval websites include:

Elsevier: The University of California on the other side of the Pacific Ocean, the world's largest HowNet, is one of the largest academic publishers in the world, with more than 2,000 academic journals such as Cell, The Lancet and New Scientist. According to Wikipedia statistics, the number of papers downloaded every year is as high as 654.38+0 billion.

Springer: short for springer Publishing House. Springer Publishing House is one of the largest science and technology publishing houses in the world. With a history of 1.70 years, it is famous for publishing academic journals. It is also the first publisher to digitize paper periodicals.