论述期刊文献集中趋势的主要成因。以《中文核心期刊要目总览》提供的数据为依据，计算了10种工程技术类期刊的莱姆库勒公式β值，绘制了F（x）～x图。

The main reasons for the tendency towards concentration of periodical literature is discussed.On the basis of the data in 《AGuide to the Core Journals of China》,the β in Leimkuhler formula of ten engineering and technology periodicals is calculated.Adrawing of F(x)-x is drawn. The β can be the criterion of the tendency towards concentration of periodical literature,the bigger the β value,the stronger the concentration.