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.

NMRShiftDB is a web database for organic structures and their nuclear magnetic resonance (nmr) spectra. It allows for spectrum prediction (currently only for carbon) as well as for searching spectra, structures and other properties. Last not least, it features peer-reviewed submission of datasets by its users.

Nomos eLibrary provides access to academic books and journals in the subject areas of law, political sciences, economics, media and communication sciences, history, sociology, education and cultural studies, European Union, health sciences. This collection is continuously extended by single e-book acquisitions by MPG libraries. The current MPI Criminal Law subscription comprises following collections: * Law 2007-2014

Nomos eLibrary provides access to academic books and journals in the subject areas of law, political sciences, economics, media and communication sciences, history, sociology, education and cultural studies, European Union, health sciences. The book selection has been continuously extended through the acquisition of individual eBook packages by MPG libraries. From volume 2022 onwards, access is given to the complete Nomos eBook portfolio. Max Planck researchers can publish their scientific work with Nomos as a print and in parallel as an Open Access eBook in the Nomos eLibrary. Further details are available on the MPDL website.

O'Reilly is an electronic reference library by providing access to technical content from leading publishers, including books, videos, proven learning paths, case studies, interactive tutorials and audio books. The learning platform gives access to the latest titles from O'Reilly and from Pearson's collection of imprints which include: Addison-Wesley Professional, Adobe Press, Cisco Press, Macromedia Press, New Riders, Peachpit Press, Prentice Hall PTR, Sun Microsystems Press, Que, and Sams. Microsoft Press titles are also available in O'Reilly.

The goal of OAIster is to create a collection of previously difficult-to-access, academically-oriented digital resources that is easily searchable by anyone.

OECD iLibrary is the online library of the Organisation for Economic Cooperation and Development (OECD) featuring its books, papers and statistics and is the gateway to OECD’s analysis and data. It also contains content published by the International Energy Agency (IEA), the Nuclear Energy Agency (NEA), the OECD Development Centre, PISA (Programme for International Student Assessment), and the International Transport Forum (ITF).

In OLC you have access more than 25 million articles from over 20,000 scientific periodicals beginning with the year of publication 1993. The Online Contents records are supplied by Swets and are updated daily.

Online Contents Educational Sciences provides access to the tables of contents of journals in the field of educational sciences. It is a subject-oriented selection of bibliographic data from the Online Contents database. This database is regularly enhanced by table of contents data from additional periodicals out of the special collections of the UB Erlangen-Nürnberg as German central subject library for Educational Sciences. It covers journal articles and reviews about various pedagogical disciplines, including home and foreign educational system, early childhood and preschool education, school and special school types, curriculum, teaching and teacher education, special needs education, vocational education.

The database OLC Mathematics and Informatics is a subject oriented selection of bibliographic data from the Online Contents database that is regularly enhanced by table of contents data from additional periodicals out of the special collections of the TIB Hannover. Currently 1,357 journals are being indexed back to the year of publication in 1993.

The Online Contents service of the Special Subject Collection Political Science and Peace Research is part of the Online Contents database. It offers access to tables of contents of more than 870 journals relevant for study and research. New journals were added until December 2013 by the Special Subject Collection. Thus the database contains approximately 1.478,600 records of journal articles and reviews.

OLC Psychology is a subject oriented selection of bibliographic data from the Online Contents database. This database is regularly enhanced by table of contents data from additional periodicals out of the special collections of the Saarland University and State Library (SULB) Saarbrücken, the central subject library for Psychology in Germany. Currently 878 journals are being indexed back to the year of publication in 1993.

Olms Online is an e-book portal providing access to following collections: * Reprints: About 400 volumes with a focus on German language and literature and on philosophy. Olms Online presents titles with additional information. These are reprints with new introductions, afterwords, notes or indexes added by the editors. * Frankfurt and Leipzig Book Fair Catalogues: Book-trade catalogues, generally referred to as book fair catalogues, offer a unique overview of German and European book production over a period of nearly 300 years (1594-1860).

Open Syllabus is a non-profit research organization that collects and analyzes millions of syllabi to support novel teaching and learning applications. Open Syllabus helps instructors develop classes, libraries manage collections, and presses develop books. It supports students and lifelong learners in their exploration of topics and fields. It creates incentives for faculty to improve teaching materials and to use open licenses. It supports work on aligning higher education with job market needs and on making student mobility easier. It also challenges faculty and universities to work together to steward this important data resource. Open Syllabus currently has a corpus of nine million English-language syllabi from 140 countries. It uses machine learning and other techniques to extract citations, dates, fields, and other metadata from these documents. The resulting data is made freely available via the Syllabus Explorer and for academic research. The project was founded at The American Assembly, a public policy institute associated with Columbia University. It has been independent since 2019. All of the syllabi in the current collection are English language documents – including from universities where English is not the primary teaching language.

The OSF Preprints search combines records from various preprint repositories, including arXiv, bioRxiv, Cogprints, PeerJ, PsyArXiv, RePEc and SocArXiv.

Developed cooperatively with scholars and librarians worldwide, Oxford Bibliographies offers exclusive, authoritative research guides across a variety of subject areas. Combining the best features of an annotated bibliography and a high-level encyclopedia, this cutting-edge resource directs researchers to the best available scholarship across a wide variety of subjects.

The platform serves as interface to over 300 journals published by the Oxford University Press (OUP) in the humanities, social sciences, law, science, and medicine. Two-thirds of this journals are published in partnership with learned and professional societies around the world. The MPG subscription enables full text access to OUP's full journal collection. It also covers article-processing charges for Max Planck authors in hybrid and selected fully open access journals offering CC-BY licenses. Further details are available on the MPDL website.

The Oxford English Dictionary is a guide to the meaning, history, and pronunciation of over half a million words and phrases, both present and past, from across the English-speaking world. It traces the usage of words through 3.5 million quotations from a wide range of international English language sources, from classic literature and specialist periodicals to film scripts, song lyrics and social media posts.

Oxford Handbooks Online is a collection of handbooks in 17 subject areas, bringing together the world's leading scholars to write review essays that evaluate the current thinking on a field or topic, and make an original argument about the future direction of the debate. For the first time, all Handbooks are available online as well is in print across the subject areas. Monthly updates introduce articles in advance of print publication and beyond the book, online-only content ensures the most current, authoritative coverage anywhere.

Oxford Reference Online is a collection of more than 200 dictionaries and encyclopedia from various subject areas. Oxford Reference Online consists of a wealth of facts, figures, definitions, and translations found in dictionary, language reference, and subject reference works published by Oxford University Press. In addition to the Premium Collection, the Western Civilization Collection is available.