依据 Web页面和 Web站点可以被搜集和分类 ,文章探讨的主题是 :WWW构成图书馆。结论是 :Web不是数字化图书馆 ,但是图书馆可以从 Web中选择搜集材料。 Web文献有两种变化形式。第一种变化形式是本文所谈论的“持续性”;第二种变化形式是 Web页面或 Web站点信息的变化。本文力求更进一步认识 Web页面和 Web站点的生存期 ,生存期的变化会影响具有 Web信息的图书馆的完整性和有效性 ,然而如果能够认识这些变化就可以进行控制和管理。 Based on Web pages and Web sites can be collected and classified, the article discusses the theme is: WWW constitute a library. The conclusion is: Web is not a digital library, but libraries can choose to collect material from the Web. Web documents have two variations. The first change is the “persistence” discussed in this article. The second change is the change in information on a Web page or Web site. This article seeks to further understand the survival of Web pages and Web sites, changes in survival will affect the integrity and effectiveness of libraries with Web information, but if you can recognize these changes can be controlled and managed.