Periodicals Archive Online is a major archive that makes the backfiles of scholarly periodicals in the arts, humanities and social sciences available electronically, providing access to the searchable full text of hundreds of titles. The database spans more than two centuries of content, 37 key subject areas, and multiple languages.

This historic journal index enables the simultaneous search in millions of citations for articles published in the arts, humanities and social sciences, across more than 300 years. It enables researchers quickly and comprehensively to identify articles relevant to their field of study and reduces what could take years of research to a matter of minutes. Journals indexed span 37 key subject areas and multiple languages.

Project MUSE is a leading provider of digital humanities and social science content for the scholarly community. Since 1995 the MUSE journal collections cover full-text versions of scholarly journals from many of the world's leading university presses and scholarly societies, with over 120 publishers currently participating.

SciELO (Scientific Electronic Library Online) is a program of the Sao Paulo Research Foundation for the cooperative publishing of open access journals on the internet. Content includes regional journals from Latin American and the Caribbean as well as titles from Spain, Portugal and South Africa. The index covers approximately 650 titles (over 350 adding content to journals already covered in the Web of Science) and contains several million cited references.

ScienceOpen is a networking platform for scholars to enhance their research in the open, make an impact, and receive credit for it. The site provides advanced search and discovery functions, combined with post-publication peer review, recommendation, social sharing, and collection-building features. The Max Planck Society covers article-processing charges for ScienceOpen Research and ScienceOpen Poster centrally. Further details are available on the MPDL website.

SocINDEX is the world's most comprehensive and highest quality sociology research database. Subject headings from a 15,000 term sociology-specific thesaurus designed by expert lexicographers and extensive indexing for books, monographs, conference papers and other sources is included. Searchable cited references are also provided.

The SpringerLink platform provides MPG staff with access to a huge collection of English and German eBooks from 2005 onwards, as well as the English and the German collection of the Springer Book Archive (1842-2004). In addition, the content of selected book series is available. Includes major reference works and dictionaries. Max Planck researchers who publish a monograph or edited volume with Springer Nature as an Open Access eBook receive a discount on the standard Book Publishing Charge. MPDL covers the costs remaining on a pro rata basis. Further details are available on the MPDL website.

The World Christian Database (WCD) provides comprehensive statistical information on world religions, Christian denominations, and people groups. Extensive data are available on 9,000 Christian denominations, 13,000 ethnolinguistic peoples, as well as data on 5,000 cities, 3,000 provinces and 234 countries.

The World Religion Database (WRD) contains detailed statistics on religious affiliation for every country of the world. It provides source material, including censuses and surveys, as well as best estimates for every religion to offer a definitive picture of international religious demography. It offers best estimates at multiple dates for each of the world’s religions for the period 1900 to 2050.