ProQuest Dissertations and Theses Global is the world's most comprehensive collection of dissertations and theses, covering materials back to the first U.S. dissertation, accepted in 1861, as well as to European dissertations from the 17th century. The database is the official dissertations repository for the Library of Congress, with 5.5 million bibliographic citations, 3 million full texts, 4,100 contributing institutions worldwide and 250,000 works added annually. Full-text coverage spans from 1743 to the present, with citation coverage dating back to 1637.

A collaborative effort of the Networked Digital Library of Theses and Dissertations (NDLTD), OCLC, VTLS, and Scirus, the NDLTD Union Catalog contains more than one million records of electronic theses and dissertations. For students and researchers, the Union Catalog makes individual collections of NDLTD member institutions and consortia appear as one seamless digital library of electronic theses and dissertations.

The integration between ProQuest Dissertations & Theses Global with the Web of Science enables seamless discovery of early career, post-graduate research from all around the world, alongside records for journal articles, conference papers, book chapters, preprints, patents, and more. ProQuest Dissertations & Theses Citation Index makes more than 5.5 million multidisciplinary dissertations and theses searchable, from over 4,100 institutions and more than 60 countries, dating back to 1637. Researchers have simultaneous access to unpublished and published scholarship that helps them to discover emerging trends, identify new areas of research and find post-graduate programs engaged in cutting-edge research. For joint subscribers of the Web of Science and PQDT Global, direct full text linking from the Web of Science to the ProQuest platform is available, giving access to 3 million full-text works from thousands of universities. Additionally, cited reference indexing and linking helps to further connect dissertations and theses to related works and discover hard-to-find sources of research.

The Document and Publication Server of the Humboldt-Universität zu Berlin is a service of the university library and the computer and media services. It offers the organisational and technical framework to all members of HU Berlin for publishing scientific documents digitally. Documents that are stored include single publications and publication series, collections, conference papers, research reports, journals (e-journals), theses and dissertations, master theses and seminar papers.

ProQuest, the company, serves the information needs of millions of researchers in libraries and institutions around the world. ProQuest, the product, is a search application providing access to a broad selection of bibliographic and fulltext databases, to the world’s largest collection of dissertations and theses as well as to three centuries of global, national, regional and specialty newspapers.

Refubium is a service of the university library of the Freie Universität Berlin. As an institutional repository it collects documents, dissertations, postdoctoral theses, and research data.

Web of Science supports more than 15 databases. You can subscribe to all of these product databases, plus perform research within an All Databases function that searches across all product databases in your subscription. You must subscribe to at least two product databases to perform an All Databases search. All Databases helps you quickly find, analyze, and share information in the sciences, social sciences, arts, and humanities across all product databases within your entitlements. Designed for both novice and professional researchers, its streamlined search process makes it easy for you to quickly find and analyze past and present available research in all fields of research.