Thesis keyword

The keyword is the document retrieval identifier of the scientific paper, and it is the natural language vocabulary that expresses the concept of the subject of the literature. The keywords of a scientific paper are words or phrases selected from their title, hierarchical title, and body that reflect the subject matter of the paper.
The keywords are proposed to suit the needs of computer retrieval, and the location is after the abstract. As early as 1963, the US chemical abstracts began to use the electronic computer to compile keyword index from the 58th volume, providing a way to quickly search the subject of literature. Today, with the rapid development of scientific and technological information, hundreds of thousands of scientific papers are published every day in the world. The academic community has already agreed to use the topic concept words to retrieve the latest published papers. The author's published papers do not include keywords or descriptors, and the literature database will not include such articles, and the reader will not be able to retrieve them. Whether the keyword is selected properly is related to the retrieval of the article and the utilization of the result.
1 Keyword classification keywords include thesaurus and free words. ?
1) The thesaurus refers to the standardized words or phrases that can be used to index the subject matter of the literature in the vocabulary such as Chinese Thesaurus and Mesh.
2) Free Words - Reflects new or new terms in the subject of the paper that have not been included in the subject vocabulary or words that are not found in the thesaurus.
2 Keyword indexing is to meet the needs of computer automatic retrieval. gb/t 3179-92 stipulates that modern science and technology periodicals should give 3-8 keywords after the abstract of academic papers. The indexing of keywords should be selected according to the principles and methods of gb/t 3860-1995 "Documentary Descriptor Indexing Rules", with reference to various vocabularies and reference books; important terms in new disciplines and new technologies not included in vocabulary As well as the name of the article, the name of the place can also be marked as a keyword.

The so-called indexing refers to the process of analyzing the literature and some features with retrieval significance such as research objects, processing methods and experimental equipment, and using the thesaurus to give the subject retrieval identifier. The subject analysis of the literature is to find out the basic elements that constitute the subject of the document through analysis in the content of the complex literature, in order to accurately index the required thesaurus. Indexing is the premise of retrieval. Without correct indexing, it is impossible to have a correct search. Scientific papers should index keywords according to the indexing method of the thesaurus, and regulate free words as descriptors as much as possible.
3 Basic principles that should be followed for indexing keywords
3.1 The principle of specificity A word can only express a topical concept as specific. As long as the corresponding specific descriptors are found in the thesaurus, the upper or lower words in the vocabulary are not allowed; if the thesaurus directly corresponding to the theme concept is not found, the upper words do match the theme concept. , you can choose. For example, “aircraft fire prevention” can find the corresponding special word “special machine fire prevention” in the thesaurus, then it must be preferred. Do not use the above-mentioned word "fire prevention" indexing, nor use the two themed words "aircraft" and "fire prevention". ?
3.2 The principle of syntactic grouping is a combination of concepts. There are 2 types of concept combinations:
Cross combination. Refers to the combination of two or more thesaurus with conceptual cross-relationships, and the result expresses a specific concept. For example: "Jet vertical landing aircraft", the words "flight plane" and "vertical landing aircraft" can be used to express the specific concept that is not in the thesaurus; "kidney stones" can be used "kidney" The two thesaurus "disease" and "stone" represent a specific concept. ?
Aspects are matched. Refers to a combination of a thesaurus that represents a thing and another descriptor that represents a certain attribute or aspect of a thing, and the result expresses a specific concept. For example: “Signal Simulator Stability” can be combined with “Signal Simulator” and “Stable”, that is, using things and their properties to express the concept of “specification; color picture tube fluorescent screen coating”, available with “color picture tube” The three phrases of "fluorescent screen" and "coating" are used to express a specific concept in terms of the three aspects of things and their state and process.

When categorizing indexing, priority is given to cross-combination, and then aspect matching is considered; the descriptors participating in the composition must be the most closely related and closest narration to the subject matter of the literature, to avoid over-the-counter combination; The concepts expressed are clear and precise, and can only express a single concept; if the concept of the topic cannot be expressed by the combination method, the most direct upper word or related descriptor can be used.
3.3 Free Words Indexing The following situations allow keywords to be indexed using free words. ?
a. The subject matter words that are clearly missing from the subject vocabulary. ?
b. Express new concepts such as new disciplines, new theories, new technologies, and new materials. ?
c. Names and important data names of regions, people, products, etc. not included in the vocabulary. ?

d. Some concepts are grouped, and when the results are polysemy, the indexed concept can also be indexed with free words. Free words are selected from other words or authoritative reference books and reference books as much as possible. The free words used must be concise, clear, and practical. After the free word indexing, there should be a record and promptly report to the thesaurus management department. ?
4 Keyword indexing steps?
Firstly, the subject analysis of the literature, to understand the subject matter and center content of the article; extract the words and phrases consistent with the theme concept from the important paragraphs of the title, abstract, hierarchical title and body as much as possible; sort the selected words According to the thesaurus, we can find out which words can be directly used as the thesaurus index, which words can be changed into the thesaurus through normalization, which the thesaurus can be combined into the phrase that refers to the topic concept; and the number can not be standardized as the thesaurus. The words, as long as they are necessary to express the concept of the subject, can be indexed as free words and included in the keyword.
In the keyword indexing, the "Chinese Subject Header" and other "Thesaurus" should be well used. The indexing process should look up the table; avoid the subject concept analysis and the word grouping is wrong; to control the free word mark The number of quotes.
For papers with English abstracts, English keywords corresponding to Chinese keywords should be included below the English abstract.