Information retrieval:
Information retrieval principle, the writing is not standardized raw data previously stored, through the induction of or split standardized means to facilitate user searching.
Types of information retrieval can be classified, literature search by entering a keyword into the search engine, the search to find only text contains key characters, which documents the final choice is determined by the scholars themselves according to the data content. Accurate data retrieval is found in the corresponding database data directly, the numerical result of the retrieval. The fact that search was carried out to find the facts recorded in the encyclopedia database, EG historical basis.
Network database retrieval tool primarily EG : yandex.com
Select the search method based on the researcher's own needs. Based on the time series, we need to understand the history of a subject, you can use the search process along. Since emerging discipline ( EG block chain) pre-recorded very little, so the use of the investigations process. Understanding of the subject development within a certain period, a certain period can be extracted using the method checks. Method retroactive to the main content of the article by article references A , then from A to find A references B , now document database can be found two layers. Loop method is a combination of these.
Retrieving way into the extrinsic pathway and the intrinsic pathway.
External approach is based on the literal meaning of the expression, a simple string matching the results obtained. Wherein the limit is to find a title title of the document containing the keyword, that particular Title limitations and topic different limits, based on the topic time limit, search character string region is a title keyword + + abstract . Responsible approach is based on academic literature to find relevant information. Number calibrated way, because the search is based on coding, not repeat or disorder. Common encoding DOI , ISSN and ISDN and so on.
The intrinsic pathway is associated with the search for the meaning of the characters. Based on the case of research papers, the approach is usually classified by subject category, but there is a dispute on the classification of new cross-disciplinary, not to use this approach. Theme approach is to search for users based on keywords, in order to ensure efficient and do not require standardization of the keyword keyword. Classification theme approach combines more than 2 types of internal approach method.
Retrieval is the need to know the rules when using the search box. Using Boolean logic to retrieve, with (the * ; or + ; non) the keyword in series, this case relates to a full-precision look into the problem of the shift, to ensure that this problem should recall, consider precision, because first precision will lose some unknown information. Use the advanced search provisions of the order of operations, namely in parentheses. Predetermined position search using the absolute and relative positions between the search fields:
Where F is the Feature , P is a paragraph , S is a sentence , W is is with and can not be reversed, N is the next and may be reversed, n- is the number of words separated by intermediate. Truncation is mainly used when retrieving only know part of the information, some of the information is written simultaneously * on behalf of all the characters. Limit your search is to limit the basic information to filter retrieval.
Modify the search range for the following search skills. To broaden the search, keywords can reduce the degree of proprietary, higher-level word keywords, use or access keyword, delete unimportant words ( EG : ADJ , XXX meaning), using truncation to retrieve and expand basic information limit ( EG to full header), the operator adjusts the position adjustment mainly n (the n becomes large), for other database retrieval. Narrowing the search range, can be specialized words, keywords hyponym, non or connecting keyword, the subject field may be reduced, the search narrowed down to the title.
Note retrieval skills. Do not use the word of undetermined significance ( EG : XXX meaning), because the meaning of the string containing all the results will reduce efficiency. Note that there are various forms of chemical terms. Do not use own words. Abbreviations find the full name.
Retrieval process is to analyze the subject, this time from the theme, subject, type of information ( Article This article was or Review ), year to consider. After obtaining basic needs, and then select the database, it should pay attention web of science are not necessarily all, because literature revenue with the site's quality threshold. Search words then, write a search expression according to the rules of the database, this process flow is cut demand assigned word, deleting big words, keyword refinement (i.e. select the appropriate keyword) and finally to Boolean logic. The results obtained after adjustment for best results.