How do full-text search engines and catalog search engines work?

Full-text search engines and catalog search engines are information search tools used to retrieve information from various sources such as websites, documents, and database. They work as follows: Full-text Search Engine: The full-text search engine will index all the documents that may contain keywords. These documents could be webpages, documents, database, electronic books, and so on. Full-text search engines will use keywords and abstracts to match the search results. If the retrieved text contains keywords, the full-text search engine will return the text along with the abstract. If the retrieved text did not contain the keyword, the full-text search engine would return other articles that might contain the keyword. Full-text search engines will return a series of matching results. These matching results may include text, paragraph, sentence, and so on. The user could select different matching results to obtain more specific information. Catalog Search Engine: 1 The catalog search engine will create a catalog tree that contains all possible files. Each file contained a unique file name and file type information. 2. The catalog search engine will use keywords and file names to match the search results. If the retrieved text contains keywords, the catalog search engine will add the text name and file type information to the node of the catalog tree. If the retrieved text does not contain the keyword, the catalog search engine will return other files that may contain the keyword. The search engine will return a series of matching results, which may include the file name, file type, file content, and so on. The user could select different matching results to obtain more specific information.