Common search engines for search functions, what is a search engine, and what are the functions of s

Google, Yahoo, Youdao, Zhongshou, Sohu Commonly used search engine directory and **Daquan: A search engine is a service that provides you with information "retrieval", which uses certain programs to classify all the information on the Internet to help people search for the information they need in the vast sea of the Internet. In the early days, search engines collected the addresses of resource servers on the Internet, divided them into different directories according to the types of resources they provided, and then classified them layer by layer.

People who want to find the information they want can enter layer by layer according to their classification, and finally reach the destination and find the information they want. This is actually the most primitive way, and it is only used when there is not much information on the Internet. As information on the Internet has grown exponentially, search engines have emerged in the true sense of the word, which know the beginning of each page and then search for all the hyperlinks on the Internet, putting all the words that represent hyperlinks into a database.

Today's search engines are no longer just searching for information on the web, they have become more comprehensive and perfect. Take the search engine authority Yahoo!For example, in March 1995, Yahoo! was founded by Chinese-American Yang Zhiyuan and others

From the beginning to the present, they have developed from a single search engine to now have a variety of network services such as e-commerce, news and information services, and personal free e-mail services, which fully illustrates the process of the development of search engines from a single to a comprehensive. However, due to the way search engines work and the rapid development of the Internet, the results of their search are becoming more and more unsatisfactory. For example, a search for the word "computer" could yield millions of pages of results.

This is due to the fact that search engines optimize search results by the relevance of the keyword, which in turn is determined by the keyword position, name, tag, etc. This is what makes search engine search results so numerous and mixed. And the database in the search engine will inevitably contain dead links due to the development and change of the Internet.

In addition to the more mature mainstream search engines such as Google, Yahoo, etc., all kinds of different search encyclopedies are also gradually emerging on the Internet today. Search Encyclopedia is a collection of search engines of different types and languages. The rise of this type of search engine has made searching easier.

Almost everything can be done "in one page".

Crawling and crawling: first discover and collect web page information on the Internet;

Establishment of indexing database: Extracting and organizing information at the same time to establish an indexing database;

Ranking: According to the query keywords entered by the user, the retriever will quickly check out the document in the index database, evaluate the relevance of the document and the query, sort the results to be output, and return the query results to the user.