MEDLINE® is the United States National Library of Medicine's (NLM®) premier bibliographic database providing information from the following fields: Medicine, Nursing, Dentistry, Veterinary medicine, Allied health, Pre-clinical sciences. as well as information from international literature on biomedicine, including the following topics as they relate to biomedicine and health care: Biology, Environmental science, Marine biology, Plant and animal science, Biophysics, Chemistry. The database contains bibliographic citations and author abstracts from approx. 5,000 biomedical journals published in the United States and in 70 other countries. MEDLINE contains well over 13 million citations dating back to 1946. NLM uses a controlled vocabulary of biomedical terms to index articles, to catalog books and other holdings. MEDLINE’s controlled-vocabulary thesaurus contains Medical Subject Headings (MeSH®) to describe the subject of each journal article in the database. MeSH terms provide a consistent way of retrieving information that uses different terminology for the same concept. Within MEDLINE’s thesaurus, MeSH terms display hierarchically by category, with more specific terms arranged beneath broader terms.

MIT Press Direct is the content platform for publications owned by the MIT Press. The Press is one of the largest and distinguished university presses in the world and a leading publisher of books and journals at the intersection of science, technology, art, social science, and design. Within the Direct to Open (D2O) model Max Planck users have access to current ebooks from selected subject collections (published between 2022 and 2024), i.e. STEM collection, art and design collection, humanities and social sciences collection. The MPG subscription also covers the complete archive collection with more than 2,500 scholarly books spanning the publishing history of the MIT Press.

The Max Planck e-Book Index provides holdings of electronic books licensed for users in the Max Planck Society.

The Max Planck Journal Index provides holdings of a great range of printed journals available within the Max Planck Society. Besides, it contains metadata of electronic journals as loaded from the EZB. The database is updated regularly from the ZDB (twice a year) and the EZB (monthly).

MPG.PuRe is the publication repository of the Max Planck Society. It contains bibliographic data and numerous fulltexts of the publications of its researchers. The repository is based on PubMan, a publication repository software developed by the Max Planck Digital Library. PuRe was introduced in the MPG in May 2009 and replaced the former institutional repository eDoc.

The MPI EVA Library Catalogue provides information on books and journals available from the Institute's library.

The library of the Max Planck Institute for the History of Science is an interdisciplinary special library focussing in its collections on the history of science. Its inventory, built up since 1994, is only available to scientists from the institute and is not part of the interlibrary loan system.

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

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.

Including Oxford Scholarship Online (OSO), the University Press Scholarship Online (UPSO) publishes new books every month from an ever-growing roster of contributing presses, each adding to the variety of subjects covered on the platform. The MPG purchased the volumes 2003-2013/2014 of 16 OSO subject collections. This selection is continuously extended by single e-book acquisitions by MPG libraries.