1, search engine
Including Google, Baidu, Bing and so on. , users can get information related to keywords such as web pages, pictures, news and videos through keyword search.
2. Database database
Including professional databases and comprehensive databases. Professional databases, such as Pub Med, IEEE Xplore and Webof Science, provide information in academic and scientific research fields. Comprehensive databases such as LexisNexis and EBSCOhost provide various types of information.
3. Online library
Such as Google Books and Amazon Kindle, provide online reading and downloading of e-books. In addition, there are some information retrieval channels in specific fields, such as professional academic libraries, electronic journals, professional social networks (such as Research Gate and Academia.edu) and online academic platforms (such as Coursera and edX), which provide academic, scientific research and educational information in specific fields.
Search reason:
1, information retrieval is a shortcut to acquire knowledge.
John Phillips, a young college student in physics department of Princeton University, borrowed relevant public information from the library, and drew the design for building an atomic bomb in only four months. The atomic bomb he designed is small (the size of a baseball), light (7.5 kilograms) and powerful (equivalent to 3/4 of the power of Hiroshima atomic bomb).
Low cost makes some countries (France, Pakistan, etc. ) wrote to the American embassy to buy a copy of his design. In 1970s, American nuclear expert Taylor received a report entitled "The Method of Making a Nuclear Bomb". Attracted by the exquisite technical design of the report, he exclaimed, "This is the most detailed and comprehensive report I have ever seen."
But what surprised him even more was that this report was written by young students majoring in economics at Harvard University, and all the information sources of this 400-page technical report were obtained from extremely ordinary and completely open books and materials in the library.
2. Information retrieval is the guide of scientific research.
During the "Apollo moon landing program" in the United States, it was found that methanol would cause stress corrosion of titanium during the pressure experiment on the fuel tank of Apollo spacecraft. Afterwards, it was discovered that it was studied more than ten years ago. The method is very simple, that is, adding 2% water to methanol.
It took more than 10 minutes to retrieve this document. In the field of scientific research and development, repetitive work exists to varying degrees in all countries of the world. According to statistics, the annual loss caused by repeated research in the United States accounts for about 38% of the annual research funding.
The research topics on chemistry and chemical engineering in Japan are repetitive with those in foreign countries, with universities accounting for 40%, private institutions accounting for 47%, and national research institutions accounting for 40%, with an average repetition rate of over 40%, and the repetition rate in China is even higher.
Refer to the above content: Baidu Encyclopedia-Information Retrieval