jcr数据库使用-西南财经大学图书馆.ppt

5年影响因子的介绍：相对于传统的2年影响因子，5年影响因子能更好的评估那些发表的论文被引用周期很长的领域中特定期刊的影响。传统的影响因子基于两年的期刊内容被引情况：即本年度期刊对于该刊前两年发表文章的引用。 5年影响因子基于本年度期刊对于前五年发表该刊论文的引用。请注意此处显示的生物化学及分子生物学期刊的五年影响因子比传统的两年影响因子要低。 * 但是，我们也会发现在地质学类目中，每一栏的五年影响因子都要比两年的影响因子高。这就与上一张幻灯片中看到的生物化学及分子生物学形成了对比。地质学研究发表的论文需要更多时间才能完全表现出它的影响力。 * * * * 174 Subject cats in SCI + 56 in SSCI = 230 Of 230, only 3 have at least 50% of their citation activity * There are two key things to note in this slide – That TIME, in this graphic, moves from left to right – from past to present – but the JCR moves from right to left. The JCR stands in the current time (more or less) and looks BACKWARD at previously published materials. It is history, not prediction. That All the citations for the JCR come from ONE year of processed source material. In this case, the year 2008. This refers to a 2008 COVER date. As you all know…2008 materials can be received as early as Autumn of 2007, or as late as yesterday. The JCR considers all materials with a publication year of 2008, processed from any point in 2004 on forward to any materials indexed in time for the JCR extraction. For the past 2 years, we have used an extraction close date of March 1. Generally, then, it means that JCR 2008 will include materials received as late as the second or third week in February. Nearly 2 million source items processed in 2008 – and all references from these articles to previously published material 42,878,592 million cited references for JCR 2008 * 其它更新功能还包括添加了Eigenfactor metrics: Eigenfactor 和Article influence，Eigenfactor MetricsTM通过特定方法测量期刊影响,提供了描述期刊影响力的更广泛的内容,现在已经被学术领域广泛接受。这些数据补充了期刊的影响因子及其他JCR计量数据, 这些计量数据是由Eigenfactor Project? 开发的–Eigenfactor Project? 是一个由华盛顿大学生物系的Bergstrom 实验室资助的非商业学术研究项目–  * The math is so thorny for these – that almost everyone is reduced to metaphorical explanations Eigenfactor considers the journal to journal citation network created by citations in the current year to any of the past 5 years.? For each journal the EF score is a