2. Modern literature consists of four elements: literary information, literary carrier, symbol system and recording method.
3. Types of literature retrieval
1) is classified according to the form of test results: bibliographic retrieval, full-text retrieval and citation retrieval.
2) According to different retrieval objects: literature retrieval, information retrieval and fact retrieval.
3) According to retrieval methods: manual retrieval and computer retrieval.
4. Appearance characteristics of documents (natural signs): title, author, source, issue, page number, year, month, type, number, language, etc. Content characteristics of documents (manual identification): subject words, classification numbers, class names, abstracts, etc. Refers to the theme of literary discussion, that is, the central content.
5. Types of document retrieval systems: According to the processing degree of extracted documents, they can be divided into catalog retrieval system, abstract retrieval system, title recording system and full-text retrieval system.
6. Types of literature information
1) According to the form of document information: text, video, audio and numbers.
2) According to the publication types of literature information: books, periodicals, government publications, scientific reports, patent documents, conference documents, dissertations, standard documents, product sample manuals and technical files. Among them, books and periodicals are general documents and others are special documents.
3) According to the carrier form of information, it can be divided into printing type, miniature type, audio-visual type and electronic type.
4) According to the degree of document information processing: level 1 document, level 2 document, level 3 document and level 0 document.
Main documents: published books, periodical papers, scientific reports, conference documents, dissertations and invention patents.
Second-hand literature: catalogue, abstract, index. A tool for searching literature information at one time.
Literature: It is divided into review research category (dynamic review, topic summary, special review, progress report) and reference tool category (yearbook, manual, encyclopedia, dictionary, encyclopedia, guide), and also has the function of literature retrieval.
Zero documents: unofficial publications, not open to the public, such as drafts, personal notes, meeting minutes, unpublished celebrity notes, oral discussions, etc.
7. Search language type
1) According to the controlled degree of the words used:
Normative language (controlled language, artificial language): take the manually controlled normative words or symbols as the search target. Such as unit words, narrative words (subject words), title words and so on.
Non-standard languages (uncontrolled languages, natural languages) such as keywords.
2) According to the information characteristics expressed by the retrieval language, it can be divided into
Languages that describe the characteristics of document content: classification language, code language and subject language (unit language, title word, keyword (non-standard language) and description word).
Language describing the external characteristics of literature: book title, publication name, article title, author, group author, citation, code/serial number.
Chinese biomedical literature database
1. Subject indexing and classified indexing are carried out according to MeSH, China Chinese Medicine Thesaurus and China Library Classification.
2. Database >; Document > record > field.
3. Default fields: Chinese title, abstract, author, keywords, subject words and publication name.
4. Wildcard words: single word wildcards (? ), any (word) wildcard (%)
5. Intelligent retrieval: only "default field" is supported, and logical phrase matching retrieval is not supported.
6. Source: periodical name+year; Volume, issue, page number
7, keyword search-surgical treatment of a disease:
1), keyword disease+"operation" (vice)
2), operation name+"method" (vice)
3)、# 1+#2
-Drugs to treat diseases:
1), disease+"drug therapy"
2), drugs+"therapeutic application"
3)、 1+2
8. After selecting a topic search, click "Topic Search" to search. After selecting classified retrieval, press "classified retrieval"
PubMed database
1, a global free biomedical literature database based on the Internet, is an authoritative biomedical database.
2. The database includes three parts: MEDLINE, citations in process and citations provided by publishers, in which MEDLINE is marked with index table lines and citations in process are marked with published-in process. The citation provided by the publisher is marked PubMed-as provided by the publisher.
3. Basic word segments
Chinese section code English section code full name English section code abbreviation
Title TI
Abstract ABstract ab
Author Authorau
Affiliate advertisement of author's unit
Journal name journal J N
Publication year Publication year
Language LA
All fields all
First author 1AU
LASTAU, responsible author
Keywords MH
Log title TA
Keywords text word TW/KW
3. Word breaker: "*" stands for 0 or more characters, even in CNKI VIP, with CBM of%.
4. Automatically convert the matching retrieval order: network thesaurus, journal title table, phrase table, author index and logical operator. If you can't find it in the four tables, you can automatically split the phrase and repeat the above process in units of words or phrases. When searching, the logical relationship between each word is AND.
5. When searching for phrases, pay attention to adding ""symbol, otherwise it will be split into independent words or phrases for logical "AND" connection.
6.AND, NOT or must be capitalized. You can add "[TI/AU]" after the search term of the field name.
Not> and> or
7. Author search: the first letter of the author's surname is blank. If you search only by last name, you must add the author field [AU].
8. Journal name retrieval: If there are special symbols in the journal name, delete the special symbols when entering the journal name and abbreviation.
9. Subject retrieval: limited to the main subject. Weighted retrieval improves accuracy.
Do not include the grid term under this term in the grid hierarchy. Don't extend it.
10, Citation Matcher: PubMed Tool-Single Citation Matcher
Periodical retrieval: more resources-periodicals in -NCBI database.
China Knowledge Infrastructure Project (CNKI)
1, China Journal Full-text Database (CJFD) is a sub-project of China HowNet source database construction, and it is the largest dynamically updated journal full-text database in the world at present.
2. The subject field is the default field, which is a combination of article title, keywords and abstract.
3. It has regular navigation function.
4, cited times to see: cited documents
Scientific guidance
1 is recognized by the industry as a high-quality academic journal (1823).
2. When searching for a special word or phrase, you need to add ""or {}, otherwise, the word will be searched as a unit using logical and.
3. Check the journal impact factor or ISSN number: click on the journal cover "About this journal" impact factor: impact factor.
4. Operator priority: or, W/n, PRE/n, AND and NOT.
5.W/n: the interval between two times is no more than n words, the order of the two words is not fixed, and the PRE/n word order is fixed. Such as influenza w/3 drugs, can not be used at the same time.
6. Author search: full name or abbreviation+surname.
7. The author field can appear with different names. It needs an author and uses a specificauthor.
8. Second search: search in the results. Within a limited range: limited within or outside the selected range: excluded.
9、
10, the latest 25 hot articles, directly jump to the result, the number of citations; quoter
1 1. Search for expression: articles found: the expression is at the top of the page.
12, single-character wildcard (? )
China Sci-tech Periodical Database
1, according to China Library Classification (1989).
2. Default field: nomination or keyword.
3. Synonym retrieval can be used in advanced or traditional retrieval, but only title, keywords and title or keyword fields can be used. There is no expression in traditional retrieval, so write down the key steps.
4. Operator "*" means AND, search in the result, "+"means or, add in the result, "-"means NOT, and delete in the result.
Knowledge is the essential content of literature, the carrier is the external form of literature, and recording is the means to link knowledge with the carrier.
Literature retrieval in a broad sense essentially includes literature storage and literature retrieval.
Catalogue retrieval system: books and periodicals
Title retrieval system: an independent article, which only pays attention to the external characteristics of documents.
Evaluation of document retrieval system: accuracy, timeliness, perfection of indexing system, depth of information indexing, recall and precision.
Indexing depth reflects the detailed degree of describing the characteristics of information content. Index degree is an important factor to determine the quality of retrieval system.
Recall ratio (r)= total amount of relevant information detected/relevant information of retrieval tools.
Accuracy ratio (P)= detected related information/total detected related information.
The retrieval language consists of retrieval title and grammar, which are equivalent, subordinate and relevant.
The basic methods of retrieval are common law, backtracking, circulation and browsing.
The basic steps of document retrieval are to analyze the subject, make clear the retrieval requirements, select retrieval tools and methods, select retrieval marks and retrieval methods, and process the retrieval results to obtain the original documents.
The symbol system of literature is pictures, characters, formulas, charts, codes, audio-visual and electromagnetic information.
Comprehensive search engine, thematic search engine and thematic search engine.
Independent sum element
Information is confidential, timely and transmissible.
Literature belongs to the solid carrier of salvation.
Brief introduction of coalbed methane database
Data index
All titles of CBM are subject-indexed according to the latest editions of MeSH Thesaurus of National Medical Library, China Traditional Chinese Medicine Thesaurus published by Institute of Traditional Chinese Medicine Information of China Institute of Traditional Chinese Medicine, and China Library Classification.
Second, the structure of CBM database and system operators
(2) System operator
Field: The data items that make up the record are fields, which reflect the specific characteristics of the document. Such as title (ti), author (au), address (ad), source (so), subject word (MeSH), keyword (KW), characteristic word (TG), publication year (PY), language (la), etc.
Record: It is the basic information unit that constitutes the database, and each record describes the appearance and content characteristics of an original piece of information. A record usually consists of multiple data items, and a record in a document database usually represents a document.
File: It is a part of the records in the database. Many large databases often contain tens of thousands of records, which are often divided into several documents to facilitate user retrieval.
Title, author, keyword abstract, source and publication year
(A) the database structure
The records of CBM database include more than 30 searchable data items.
AB Abstract Advertising Address (First Author Address)
AU author CN domestic code (domestic periodical code)
CL classification number, CT characteristic words, FS funding category MH keywords
The publication year of PY is ISSN (International Journal Code) Volume VI.
Number of RF references of PT document type (number of references)
(SO) source (compound fields: TA, PY, VI, IP, PG) TA journal name.
TI Chinese topic TW keywords
1. Boolean logic operator
A. Logical AND
B. logical or
C. Logical "no"
Three, coalbed methane database retrieval operators
(2) System operator
The precedence order of Boolean logic operators is () > NOT >；; And> or,
2. Wildcards: (1) single-word wildcards? : Replace characters. For example, "door? Pulse ",detectable: portal vein, portal vein artery, etc.".
Attention:? Must be at half angle.
(2) Any wildcard%: Replace any character. For example, "hepatitis% vaccine" can be detected: hepatitis vaccine, hepatitis virus gene vaccine, live attenuated hepatitis vaccine and inactivated hepatitis vaccine.
3. Performer/phrase retriever ""
As a phrase or containing special symbols such as "-"and "(",search terms are marked with English half-width double quotation marks, such as "1, 25-(OH)2D3".
Four, coalbed methane retrieval method
1, basic search 2, subject search 3, classified search 4, periodical search 5, author search 6, limited search.
1, basic search
Disadvantages: large retrieval error, low precision and recall.
2. Topic retrieval
Subject words are also called descriptors.
It refers to the technical terms that can represent the essence of the literature theme and have been strictly standardized.
Standardization: Synonyms with different expressions are forced to be represented by one word by authorities. Networked thesaurus, Chinese thesaurus.
Subject retrieval: the subject concept based on the content of literature is beneficial to recall and accuracy.
Advantages:
Conducive to a comprehensive and accurate investigation
You can easily expand or narrow the search range (expanded and not expanded, weighted and unweighted).
It is convenient to define the main concepts and aspects of literature.
(with one or more sub-keywords)
Disadvantages:
It is difficult for non-professionals to master the indexing of subject words.
3. Classified retrieval
Classified retrieval: refers to the collection of documents by discipline or specialty and the use of ethnic retrieval methods. If you have a comprehensive collection of documents on a certain subject or already know the subject classification system of the required documents, you can search from the classification way.
According to the classification number and name of China Library Classification and Medical Professional Classification Table.
5. Author search
You can retrieve all the literatures published by authors contained in the database. If the first author option is marked at the same time, the retrieval results are all documents of the first author.
6. Limited search
Restricted retrieval: it is to integrate the commonly used restrictions such as year, literature type and research object into a dialog box to facilitate retrieval.
Verb (abbreviation of verb) display and storage of search results
Display results: * * There are three formats:
The system defaults to the title record format, which displays: title, author, author unit and source.
Format display: title, author, author unit, abstract, source, keywords, subject words and characteristic words.
Detailed Format: Displays all fields. Based on the abstract format, add references and funding categories.