In this paper we discuss recent directions concerning the structural analysis of science documents and cognitive aspects of document elements aiming at document comprehension. Structural analysis of documents, according to text comprehension theory, promotes document understanding and enhances universal accessibility of documents. We outline the process of structuring science documents and activities for comprehension using the authoring tool ReTuDiSAuth. This process improves universal accessibility of document supporting authors to structure text and text activities for students with different abilities, requirements and preferences.