Literature retrieval is divided into data retrieval: retrieval based on data in literature. Such as molecular formula, chemical molecular formula, etc. Fact retrieval: search for the time, place or process of something by taking the facts in the literature as the object. Literature retrieval: searching for related literature on a certain subject with literature as the object.
Compared with the storage identification of documents, if the retrieval identification can be consistent, it is called matching, and the hit document can be obtained.
Question 2: 1 What kinds are there? Is Boolean logic retrieval included in literature retrieval technology?
Using Boolean logic operators to logically combine search words or codes is the most commonly used technology in modern information retrieval systems. There are three commonly used Boolean logic operators, namely logical OR, logical AND and logical NOT.
2. Intercept retrieval
Interception retrieval is a very common technology in computer retrieval system. Due to the word formation characteristics of western languages, the singular and plural forms of nouns are often inconsistent in retrieval; English and American spellings of words with the same meaning are inconsistent; Adding prefixes and suffixes with different properties to the stems can lead to many words with similar meanings, and so on. This is using cut-off retrieval.
3. Location retrieval
Location retrieval is also called full-text retrieval and proximity retrieval. The so-called full-text retrieval is to search by using the natural language in the record, and the logical relationship between words is combined with the position operator to limit the relative position between the search words. This is a technical method that does not depend on thesaurus and can directly use free words to search.
4. Limited field retrieval
Field-limited retrieval refers to a retrieval method that limits search terms to one or several fields in database records. In the retrieval system, there are usually two kinds of fields available for retrieval in the database: the basic fields that express the characteristics of literature subject content and the auxiliary fields that express the external characteristics of literature.
5. Weighted retrieval
Weighted retrieval is a quantitative retrieval technology provided by some retrieval systems. Weighted retrieval, like Boolean retrieval and truncated retrieval, is also a basic retrieval method of literature retrieval, but different from them, the focus of weighted retrieval is not to determine whether a search word or string exists in the database and what is the relationship with other search words or strings, but to determine the degree of influence of a search word or string on whether a document hits after satisfying the retrieval logic.
6. Clustering retrieval
Clustering is to classify unclassified things into the same category without knowing how many categories they should be classified into, and to classify information with similar attributes into the same category according to the different internal attributes of things.
Question 3: What is the literature retrieval course? Literature retrieval is a tool course, which mainly teaches retrieval tools, methods and resources. Every developer will have his own characteristics, some pay attention to the retrieval of paper documents, and some pay attention to the retrieval of electronic documents. The main purpose of this course is to help you find resources effectively. For example, if you want to know a person, you need to read some biographies of him. Search will tell you what biographies this person can use and how to use them, which can improve your work efficiency very pertinently. So, I think you should calm down and study this course well.
Question 4: What does literature retrieval mean? Information retrieval refers to the process of organizing and storing information in a certain way and finding out relevant information according to the needs of information users, so its full name is also called "information storage and retrieval", which is information retrieval in a broad sense.
Narrow information retrieval only refers to the second half of the process, that is, the process of finding the required information from the letter, which is equivalent to what people usually call information search.
Question 5: What is literature information retrieval? Literature information retrieval is divided into broad sense and narrow sense. The generalized literature information retrieval includes two blinking processes: the storage and retrieval of literature information. Document information storage is a process of collecting, indexing and recording document information, arranging it in order and compiling a document information retrieval system. Literature information search is the process of finding out the specific information that users need from a large number of literature information, that is, comparing the characteristics of the problems expressing users' information needs with the signs in the retrieval system to find out the consistent information. With the development of computer technology, literature information retrieval has entered the computerized stage from manual retrieval, and it is developing in the direction of information processing automation, retrieval culture, intelligence and networking, and its retrieval content, application field and promotion scope are also expanding rapidly. Due to the diversity of users' information needs, information retrieval technology is constantly developing and changing, which leads to various types of information retrieval. According to the retrieval object, it can be divided into data retrieval, fact retrieval and literature retrieval; According to retrieval methods, it can be divided into manual information retrieval and computer information retrieval; According to the retrieval requirements, it is divided into strong correlation retrieval and weak correlation retrieval; According to the nature of retrieval, it can be divided into fixed-topic retrieval and retrospective retrieval; According to the information form of retrieval, it can be divided into text retrieval and multimedia retrieval.
Question 6: What does the document retrieval fee mean? Generally, there is no retrieval fee for searching in Baidu and Google, but if you search for some professional knowledge, or if a merchant sells it to a search engine, you will be charged. Searching professional papers and periodicals in China HowNet and Wanfang Database generally requires a retrieval fee, which is not a free service. On the other hand, people buy foreign advanced literature to serve you, of course, but the fees are generally different ~ ~ depending on what you are searching for.
Question 7: What is the standard number of literature retrieval? There are many kinds of documents, such as books, periodicals, dissertations, patent documents, conference documents, standard documents and technical documents. One of them is a standard document. Both international standards and national standards have standard numbers. For example, GB/T 77 14-2005 "Rules for the Description of References after Documents" is a country. It is a good method to retrieve standard documents by using standard numbers.
Question 8: What is the purpose of learning literature retrieval?