在多元異質的資訊環境中，如何找到真正適切的資源已經成為使用者最大的負擔；數位圖書館相關研究與實作計畫蔚為風潮，各機構投下龐大的經費將資料數位化，或購買數位資源，提供給讀者使用，然而內容或有重複，或檢索功能各異，如何讓使用者知道他要找的資料在那一個資料庫，如何將這些數位化資源發揮最大的使用效益，整合檢索成為一個重要的課題。本文主要在探討目前兩種在數位圖書館環境中普遍被採用的互通檢索協定：OAI與OpenURL，說明這兩種機制的設計原理、運作方式，並比較二著之間的差異，此外，無論是那一種互通檢索機制，數位資源的唯一識別碼是連結數位資源的重要關鍵，因此本文也針對數位資源命名問題做深入的分析，並以DOI為例，說明其目前與CrossRef、OpenURL、SFX一起運作的情況。

　　　　　In the information environment with diverse heterogeneity, users are burdened with the problem to find appropriate resources. Because of the rage of researches and implementations in digital library, every institution invests a lot of money in digitizing their collections or in purchasing digital resources for users. However, different vendors have their own closed interfaces to support their services and may provide the same content. Thus, to develop integrate search systems becomes an important issue to make the best use of digital resources. This paper focuses on two protocols of interoperability: OAI and OpenURL. We explain their designs and, how they work. We also indicate their differences. Besides, the unique identifier to digital resources is another key issue. Therefore, we analyze the schemes of digital resources, and explain how DOI works with CrossRef, OpenURL, and SFX.