连词作为语篇构成的重要部分，一直是系统功能语言学的研究对象。本研究的目的是探究连词的功能，以及它们和特定语篇的知识结构之间的联系，所以选取历史学和物理学两个学科的代表性作品：Sapiens: A Brief History of Humankind 和 Introduction to Many-body Quantum Theory in Condensed Matter Physics来研究它们语篇中的连接关系和具体的连接标志词。本研究使用Word搜集两书中出现的连接标志词及其出现频率作为数据，使用Excel统计数据。将统计出的具体连接标志词归类于四种连接关系后，出现的学科差异将通过分析样本语段来解释。分析过程会分成微观和宏观两方面，微观方面即具体连接标志词的语义分析，宏观方面指的是各个学科语篇的知识结构分析。本研究的结果总结了历史作品和物理作品中使用的具体连词，对比得出两种作品连词使用的差异，通过样本语段分析后得出差异解释，进而分析两个学科语篇中连词和其知识结构的联系。本研究的意义在于可以对两个学科的学习者提出阅读和写作学术语篇的建议。学习者通过了解不同学科的连词使用将优化他们的学习策略。

As an important part of discourse construction, conjunctions have been the object of many systemic functional linguistics studies. With the purpose of exploring the functions of conjunctions and their link to certain knowledge structure of discourses, this study chooses two typical history and physics works: Sapiens: A Brief History of Humankind and Introduction to Many-body Quantum Theory in Condensed Matter Physics to look into the conjunction relations and specific conjunction signal words in them. The specific conjunction signal words from the two books were collected by Word and were calculated by Excel. The analyses consist of semantic analysis of specific conjunction signal words and the knowledge structure analysis of each discipline. Results of the study summarize the usages of specific conjunctions in a history book and a physics book, demonstrate the contrasts of the history and physics discourses in terms of conjunctions, provide explanations of the contrasts with sample discourse analysis, and analyze the link between the conjunction usages and the knowledge structure of the discourses of the two disciplines. The significance of this study is to provide suggestions for learners when reading and writing academic discourses of different disciplines. They are supposed to optimize their learning strategies with the knowledge of conjunctions in different disciplines.