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献给@黎大页子 和中山大学大气科学系王磊老师。
ISI (Institute for Scientific Information)由Eugene Garfield于1960年创办,后来被Thomson Scientific & Healthcare 于1992年收购,于是就成了现在有名的Thomson ISI。现在,它是Thomson Reuters Corporation公司Healthcare & Science部门的一部分。关于Thomson Reuters Corporation(网址:http://thomsonreuters.com/ ),它是Thomson公司在2008年收购Reuters集团后改名而成了,现在是一个年收入达130亿美元的跨国大公司,专门提供信息服务。
ISI提供文献数据库(bibliographic database)服务,它的业务集中在引文索引和分析(citation indexing and analysis)上,旗下有名引文索引数据库包括Science Citation Index (SCI), Social Sciences Citation Index (SSCI), and the Arts and Humanities Citation Index (AHCI),这些都已经被整合到Thomson Reuters旗下的ISI Web of Knowledge平台(http://www.isiknowledge.com/)
下面要介绍的就是有名的JCR了。通过ISI Web of KnowledgeSM可直接访问期刊引用报告(Journal Citation Reports 简称JCR)。它是一个独特的多学科期刊评价工具。网络版JCR是唯一提供基于引文数据的统计信息的期刊评价资源。通过对参考文献的统计汇编,JCR可以在期刊层面衡量某项研究的影响力,显示出引用和被引期刊之间的相互关系。JCR的每一期刊的相关数据包括测量期刊影响力的影响因子(Impact Factor)和文章发表后被引用的快速程度指标立即指数(Immediacy Index),以及有关引用模式和一般源数据的信息。
JCR中常用的词语如citation为引文的意思,citing是引用的意思,cited是被引用,cites是(被)引用次数。JCR还定义了各项指数,如“Impact Factor”、“Immediacy Index”、“Cited Half Life”和“Citing Half Life”等四项指数。先在下面列出定义,然后以1996年Science杂志为例具体阐释。
参考网址:
http://blog.sciencenet.cn/home.php?mod=space&uid=70202&do=blog&id=36242
http://www.lib.tsinghua.edu.cn/service/SCIcenter/sciimpac.html )
Impact Factor
Impact Factor measures how often articles in a specific journal have been cited.The total number of quotes during a year of the two immediately preceding years' issues, for example quotations in 1994 of the journals published in 1992 and 1993, are weighed against the number of articles published in 1992 and 1993 in that journal.
Example
The journal Cell has an impact factor of 39.191, i.e. every article published in issues of Cell in 1992 and 1993 was quoted in 1994 an average of just over 39 times. Every article in Nature for the same period was quoted in 1994 just over 25 times.
Immediacy Index
Immediacy Index measures the average number of times that an article, published in a specific year within a specific journal, is cited over the course of the same year.
Example
The journal Cell contained 450 articles in 1994. These articles were in the same year quoted 3,037 times, i.e. each article was quoted on average 6.75 times (=Immediacy Index).
Read more about Impact Factor and Immediacy Index at ISI
Cited Half-life
Cited Half-life measures the number of years, going back from the current year, that account for half the total citations received by the cited journal in the current year.
Example
The journal Cell is given the figure 4.4, i.e. half of all the quotations from the journal Cell in the year 1994 referred to articles published in the last 4.4 years. The remaining half, then, concerns articles older than 4.4 years.
Read more about Cited Half-life at ISI
本来想把第二个网址的东西加上去,不过看起来很不美观,也对我们的作用不大,愿意去的自己去看吧。
行文最后,附赠上一份METEOROLOGY & ATMOSPHERIC SCIENCES学科的期刊排名(按照Impact Factor排序,2010):
见附件
METEOROLOGY & ATMOSPHERIC SCIENCES(Impact Factor)小清新.xlsx
(18.55 KB, 下载次数: 46)
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