论文零被引率是指一个国家、机构、期刊或个人某年出版的文档集合中,在出版后的某个特定引用时间窗口中未被引文档的数量或比例.它是科学出版领域中普遍存在的一种现象,然而当前的引用分布研究文献过多地关注至少被引一次论文的引用分布情况,而对论文零被引率的演变规律关注甚少.为此,本文从国内外图书情报学领域期刊中,选取6本不同影响力期刊为研究样本,实证分析了6本期刊1990—1993各年出版的论文在出版后0～19年不同引用时间窗口中论文零被引率的时间演变规律,以及1990—2012各年论文出版后当年、三年和六年零被引率的年度变化规律.实证分析发现:①除日本多语言期刊《图书与情报》(LIS)之外,其他5本期刊论文零被引率的时间演化规律能够很好地被一个三参数负指数模型:P(Xt=0)=K+Ae–S×t拟合,拟合优度(R2)都达到96％以上;②除日本《图书与情报》(LIS)期刊外,其他5本期刊论文零被引率随引用时间窗口变大而形成一系列具有"开始下降较快,随后非常缓慢地下降,直至一个非常低且稳定的水平线"特征的凹形曲线;并且此5本期刊睡眠系数S区间值大小与它们的下降幅度区间值大小的方向一致,期刊的下降幅度越大,越易于较快达到一个稳定的、变化非常少的水平,从而导致一些未被引的文献在此后的长时间内处于睡眠状态;③6本期刊论文零被引率的年度变化规律显示,随着时代的发展,图书情报学领域期刊论文的传播与利用速度越来越快.除日本《图书与情报》(LIS)论文零被引率较高,且历年变化较小外,其他5本期刊论文零被引率,尽管历年变化较大,但总体呈现下降趋势.%The non-citation rate refers to the proportion of articles that do not receive a single citation within a given citation time frame after publication. The current literature on citation distribution focuses on the distribution of arti-cles receiving at least one citation, while the time-dependent distribution of uncited articles is seldom studied. Therefore, a bibliometric analysis of time-dependent distribution of uncited library and information science (LIS) ar-ticles published in six journals with different impact factors is executed. We perform an empirical analysis of the time-dependent regularity of the percentages of uncited publications in different citation time-windows (0 to 19 years) following their publication during 1990-1993 period in six selected journals. Furthermore, we also analyze the annual distribution regularity of the percentages of uncited publications following their publication during 1990-2012. Through the above analysis, we found: (1) Time-dependent distribution curve of the percentages of uncited publica-tions (excluding LIS publications) over 20 different citation time windows for five journals can be fitted well using a three-parameter negative exponential model: P(Xt=0)=K+Ae-S*t and the goodness of fit (R2) value for each journal is above 96％; (2) In the initial citation time window, the percentage of never-cited papers in each journal is very high. However, as the citation time window becomes wider, the percentage of never-cited papers (excluding LIS papers) for five journals, begins to drop rapidly at first, and then drops slowly, approaching a very low stably horizontal line after going through an infinitely long citation period. In addition, the total degree of decline for these five journals is very large. Furthermore, the change in the sleep coefficient "S" values for these five journals has the same direction as the change in dropping amplitude values for percentages of uncited publications as the time elapsed. This means that when percentages of uncited publications drop more quickly to a very low stably horizontal line with very few changes, the publications that have not been cited will have a longer sleeping status, until they are woken up or found; (3) Annual distribution regularity of the percentages of uncited publications for six journals reveals that the speed of spread and utilization of publications have increased due to the development of science and technology. As an illus-tration, annual distribution regularity of the percentages of uncited publications (excluding LIS publications) for five journals have shown a continuous dropping trend, although there is a big annual fluctuation. The percentages of un-cited publications for LIS have shown a very high value and very low annual change.
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