Abstract The keyword lists are rich in terminology and as such, they are also characterized by great semantic ambiguity, which presents the problems of synonymy and polysemy typical of uncontrolled language, which is both an advantage and a drawback. However, assigning keywords has gained particular importance in the current open scientific communication ecosystem in digital environments, mainly in the academic dissertation and repositories of theses. This article reports a study on the organization of knowledge, using subject-access metadata of master's theses from the digital repository of the University of Sao Paulo (USP), Brazil, applying analytical techniques to a big amount of data. The objective was to analyze the number of keywords in each record and keywords repeated in the title and abstracts of the dissertations in Portuguese and English. The analysis of the 48,501 metadata records of master's theses submitted to the repository, between 2001 and 2019, presents a total of 223,867 keywords in Portuguese, with an average of 4.62 keywords per record, and a total of 216,521 keywords in English, equivalent to an average of 4.59 per record. Although, the attribution of keywords in Portuguese and English by the author is an economic way to expand access to the content of theses and dissertations in institutional repositories, it is necessary to define rules for authors about the choice of keywords and the preparation of the abstract, as well as its translation into English. The task of controlling keywords requires a partnership between authors and librarians who can enrich the quality of indexing languages.

中文翻译：

---

作者提供的 ETD 主题访问元数据：关于巴西学术知识库中关键词、标题和摘要的案例研究

摘要 关键词列表术语丰富，语义歧义大，呈现出非受控语言典型的同义多义问题，有利也有弊。然而，在当前数字环境中开放的科学传播生态系统中，分配关键字变得尤为重要，主要是在学术论文和论文库中。本文报告了一项关于知识组织的研究，使用来自巴西圣保罗大学 (USP) 数字存储库的硕士论文主题访问元数据，将分析技术应用于大量数据。目的是分析每条记录中的关键词数量以及葡萄牙语和英语论文标题和摘要中重复的关键词。对2001年至2019年间提交给知识库的硕士论文48501条元数据记录的分析显示，总共有223867个葡萄牙语关键词，平均每条记录有4.62个关键词，总共有216521个英语关键词，相当于一个每条记录的平均值为 4.59。尽管作者对葡萄牙语和英语关键词的归属是一种扩大访问机构知识库中论文和学位论文内容的经济方式，但有必要为作者定义有关关键词选择和摘要准备的规则，以及将其翻译成英文。