A search engine is an information retrieval system in the World Wide Web environment, also known as a retrieval engine or a query engine. According to the definition of the Encyclopedia Business Card, a search engine refers to a system that collects information on the Internet according to a certain strategy and uses a specific computer program, organizes and processes the information, and displays the results to users to provide retrieval services for users.
A search engine can receive a user’s query request through the Internet, search and find information on the Internet in a certain way, understand, extract, organize and integrate the information, and provide retrieval services to users, thereby playing the role of information navigation. Simply put, a search engine is a system that indexes and retrieves information resources on a www site. It is mainly responsible for organizing information and providing information as needed, and is known as a “network portal”.
When people encounter doubts and problems that need to be understood or solved, the search engine on the Internet is a tool for “teaching and solving doubts”. Just like “Baidu, you will know”, in the face of a vast amount of information, a search engine as a system can find the required information from a large amount of information and provide it to users. Nowadays, people are used to using search engines to find travel information, commodity prices, news, stocks, entertainment gossip and other information. Search engines have become a very important information portal.
Classification of search engines
Search methods are a key link in search engines, which can be roughly divided into four types: full-text search engines, meta search engines, vertical search engines and directory search engines. They have their own characteristics and are suitable for different search environments. Therefore, flexible selection of search methods is an important way to improve the performance of search engines. Full-text search engines use crawlers to crawl all relevant articles on the Internet for indexing; meta search engines are secondary search methods based on multiple search results and integrate them; vertical search engines are a professional search method for rapid retrieval of data in a specific industry; directory search engines rely on manual collection and processing of data and place them under classified directory links.
1. Full-text search engines
General network users are suitable for full-text search engines. This search method is convenient, simple, and easy to obtain all relevant information. However, the information searched is too complex, so users need to browse and identify the required information one by one. This search method is very effective, especially when the user does not have a clear search intention.
2. Meta search engine
Meta search engine is suitable for collecting information widely and accurately. Different full-text search engines have different performance and information feedback capabilities, resulting in their own advantages and disadvantages. The emergence of meta search engine just solves this problem, which is conducive to the complementary advantages of various basic search engines. Moreover, this search method is conducive to global control of basic search methods and guides the continuous improvement of full-text search engines.
3. Vertical search engine
Vertical search engine is suitable for retrieval with clear search intentions. For example, when users buy air tickets, train tickets, bus tickets, or want to browse online video resources, they can directly use industry-specific search engines to obtain relevant information accurately and quickly.
4. Directory search engine
Directory search engine is a commonly used retrieval method within the website. This search method aims to integrate and process the information within the website and present it to users in directories. Its disadvantage is that users need to know the content of the website in advance and be familiar with its main module composition. In short, the scope of application of the directory search method is very limited, and it requires high labor costs to support maintenance.