In the establishing anniversary of the two biggest Digital Object Identifier (DOI) registration agencies all over the world, Crossref and DataCite, the paper intends to provide an overview of the development and approaches and of DOI and DOI services, from which scholarly communication has benefited greatly. At first, the author explores the initiation of DOI and differences of DOI from other persistent identifiers. After that, DOIs for different kinds of objects and DOIs’ value in enhancing scholarly communication is discussed; then, in the second part, DOI services at different levels in a pyramid and those particularly in Germany are described. The active involvement of the library world are also introduced here; finally, the current situation and prospects as well as some issues dealing with DOIs and DOI services are investigated in the last part of the paper.

中文翻译：

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数字对象标识符 (DOI) 和 DOI 服务：概述

在全球最大的两个数字对象标识符 (DOI) 注册机构 Crossref 和 DataCite 成立周年之际，本文旨在概述 DOI 和 DOI 服务的发展和方法，并从中受益学术交流大大。首先，作者探讨了 DOI 的起源以及 DOI 与其他持久性标识符的区别。之后，讨论了不同对象的DOI以及DOI在促进学术交流中的价值；然后，在第二部分中，描述了金字塔中不同层次的 DOI 服务，特别是在德国的服务。这里还介绍了图书馆界的积极参与；最后，