摘要：

【目的】全面分析国际权威科技期刊非可被引文献（NCD）的引证特征以及其对影响因子（IF）的贡献。【方法】选择2014年被SCI数据库收录的、IF较高且发文数量较大的10种国际权威科技期刊为研究对象,统计2年引证时间窗口下,各刊可被引文献（CD）数量、NCD数量、被引频次、自引等情况;分析NCD的被引和NCD对CD的施引情况;最后对不同类型NCD的引证效率以及其对IF的贡献进行研究。【结果】10种国际权科技威期刊发文数量、被引频次、自引量百分比较高的NCD类型是社论、信稿、科技新闻,3种文献引证效率也较高;NCD的被引量和NCD对CD的引用量在IF被引量中占据很大一部分,最高达42.66%;NCD对IF的贡献率最高达32.83%。【结论】NCD不仅可被引而且还对文献进行施引,社论、信稿、科技新闻对期刊被引频次和IF的贡献较高,NCD对IF的贡献率不容忽视。

关键词: 非可被引文献, 可被引文献, 引证特征, 影响因子

Abstract:

[Purposes] This paper aims to analyze the citation characteristics of non-citable documents（NCD） of international authoritative journals and their contribution to the journal impact factor（IF） in an all-round way.[Methods] We search ten international authoritative journals which are obtained from the SCI in 2014, count the numbers, citation frequency, self citation of CD and NCD,analyze citation frequency of all to NCD,NCD to CD under the two-year cited time w indow,and research the citation efficiency and the contribution rate of different types of NCD.[Findings] Among the ten international authoritative journals,The NCD types which had the highest rate of the number of papers, the citation frequency, and the self citation are editorials,letters, science and technology news, which also have a higher citation efficiency.The citation frequency of NCD and the citation frequency of CD cited by NCD occupy a large part in the citation of IF,which has reached 42.66%atmost.The contribution of NCD to IF is 32.83%.[Conclusions] NCD can not only be cited, but also could lead to the documents that are needed.Editorials, letters and news items have higher citation frequency and contribution to IF of the journal.Meanwhile, the contribution of NCD to the journal's IF can not be ignored.

Key words: Non-citable document, Citable document, Citation characteristics, Impact factor