分析目录学主要是描述目录在科学方面的作用。分析目录学关注作为实体的图书全方面的研究：历史、外形特征、文本制作方式及影响，
本文分析了数字时代下目录学变革实践基础的变化，侧重讨论了随之而来目录学功能相应的延伸。
This paper discusses the changes of practical basis of the development of Bibliography in digital area, particularly relates the development of functions of Bibliography.
《揅经室外集》是目录学史上一部重要的著作，文章由分析《外集》的成书，论述了阮元在《外集》中所起的主导作用；
I point out the leading role played by Ruan Yuan in the edition and systematically analyze the abstract style inherited from SiKuQuanShu and the reason why it is better than that of SiKuQuanShu.
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