ProQuest Dissertations and Theses: Global (PQDT Global) is a world-renowned full-text database for doctoral and master's theses. It serves as the official repository for digitized doctoral and master's theses resources in the United States at the Library of Congress. PQDT Global collects and preserves the academic achievements of graduate students worldwide. The database includes over 6.4 million doctoral and master's theses from more than 4,100 universities or scientific research institutions in over 70 countries/regions worldwide, with more than 4.1 million available in full text. It covers various fields, including science, engineering and technology, agriculture, biology, medicine, psychology, philosophy, humanities, and social sciences. The full texts date back as early as 1743, and citations date back to 1637.