1. http://scholar.google.com/
Although it is still in beta version, I personally think it is already very good and powerful. Google academic search filters out a large amount of junk information from common search results, lists different versions of an article and the number of times it is referenced by other articles. However, the search results are not listed in the order of authority (such as the impact factor and number of references, most of the first few pages may be Chinese journal articles.
2. http://www.scirus.com
Scirus is one of the most comprehensive and comprehensive search engines for scientific literature on the Internet. It was developed by Elsevier Science Publishing House to search journals and patents! Scirus covers the following disciplines: agriculture and biology, astronomy, biological science, chemistry and chemical engineering, computer science, earth and planetary science, economics, finance and management science, engineering, energy and technology, environmental science, linguistics, forensic science, life sciences, material science, mathematics, medicine, nervous system science, pharmacology, physics, psychology, social and behavioral science, sociology.
3. http://www.base-search.net/
Base is a multidisciplinary academic search engine developed by the Library of Bielefeld University in Germany. It provides integrated search services for heterogeneous academic resources around the world. It integrates the library catalog of the University Library of Beaufort Germany and data of approximately 160 open resources (more than 2 million documents.
4. http://www.vascoda.de/
Vascoda is a prototype of cross-discipline portal. It focuses on the aggregation of specific topics and integrates library collections, document databases, and additional academic content.
5. http://www.goole.com/
Compared with Google, we found that some good things that Google cannot find can be found. Its interface is simple, powerful, and fast. Yahoo and Netease use its search technology. You can try it.
6. http://www.a9.com
Google is in the same level of search engine. It was launched by Amazon.com. The web result is based on Google, so it is guaranteed to be at the same level as Google. In addition, Amazon's book search and personalized features are added: it mainly records your search history. It is still beta, but it feels good after the trial. I recommend it to you for a try, but the disadvantage is that there is no Chinese content in the book search.
7. http://www.ixquick.com
Strictly speaking, it is not a search engine, but an information overpass connecting search engines and network users. The new generation of search engines came into being. ixquick meta-search is currently the most brilliant new star. However, ixquick is still unfamiliar to most domestic users. I will not describe the many unique features of ixquick. I will only introduce the database password that we are most concerned about.
Usage: Enter ixquick first, and use the "ProQuest" database as an example. Enter ProQuest Username Password History Online and click search to see the results. The first page contains the 6th ProQuest username and password, let's look at the 4th results "HB Thompson subdomains online databases", that is, http://homework.syosset.k12.ny.us/onlinedbs/hbtdatabases/. this is a password page. Select magazines & journals, there are multiple database passwords, including EBSCO, electric library Elementary, electric library Elementary, Proquest platinum (in school), Proquest platinum (remote), and uesrname and passwor. D. Try EBSCO. OK. Log in successfully.
8. http://vivisimo.com/
CMU works, which classify the search content, so that you can make effective choices and compare them with other features. Supports classified search, and the retrieval speed is good. For example, you can find a large number of EBSCO passwords in a few minutes.
Http://search.epnet.com/
User ID: Mountain
Password: Ridge
You can try this password.
Http://www.findarticles.com/
A good tool for retrieving free paper. After entering the webpage, we can see that he has three functions: driecloud web Article, which is very helpful to us. You can try to enter the articles you are looking for and there will be a lot of discoveries!
Http://www.sciseek.com/Sample
It doesn't feel very useful, and there isn't much content. It mainly relies on users to add URLs and provide information search engines. The search function is also poor, and common keywords are input, the matching content is often not found.
11. http://www.chmoogle.com
Click now or jump to the http://www.emolecules.com, in this search engine can search for more than 10 million kinds of chemical information or the corresponding suppliers, and chemblink is a bit similar, but the chemical information provided is not chemblink details, different from this, the search engine provides a chemical structure search (the search box for Online Chemical Structure Drawing is available on the home page ).
Http://www.ojose.com/
Ojose (online journalsearch engine, online journal search engine) is a powerful free scientific search engine. With ojose, you can find, download, or buy resources for nearly 60 databases. However, the operation is complicated.
13. http://citeseer.ist.psu.edu/
A search engine for computers and information science.
14. http://hpsearch.uni-trier.de/
Expert personal homepage Search Engine
Http://cnplinker.cnpeak.com/
In order to provide readers with a comprehensive network platform for convenient and convenient access to various types of journals and documents abroad, CPIC organized and developed the cnplinker (cnpiec Link Service) online database retrieval system, and officially activate and run. Cnplinker is the "" service. Currently, cnplinker mainly provides query and query of the contents and abstracts of about 3600 foreign journals, electronic full-text links, and domestic collection query functions of journals. and always maintain data consistency and up-to-date with foreign publishers.
Comment: only the foreign language search function is provided, but the full text cannot be obtained. I personally think it is not ideal.
Http://guoxue.baidu.com/
Baidu Chinese learning can now search and read ancient cultural classics from the pre-Qin Dynasty to the late Qing dynasty. The content involves various departments of the scriptures, history, sub-databases, and datasets.
17. http://infomine.ucr.edu/
Nfomin is an academic search engine established by University of California, Wake Forest University, National University of California, Detroit University and other university librarians. It provides online academic resources for university staff, students, and researchers.