The union catalog lists the holdings of all scientific libraries in Hessen and Rheinhessen. Inter-library loan requests may be submitted.

HighWire Press is a division of the Stanford University Libraries, which produces the online versions of more than 1000 peer-reviewed journals mainly in the area of life sciences (biology, chemistry, medicine), supplemented by content from the social sciences. HighWire-hosted publishers have collectively made more than 2 million articles available via the internet for free. -- Portal der Stanford University für elektronische Zeitschriften aus den "Life Sciences" (Biologie, Chemie, Medizin) und ergänzend den Sozialwissenschaften. Ausgewertet werden mehr als 1000 Zeitschriften, die durchsucht werden können. Mehr als 2 Millionen Artikel stehen kostenlos im Internet zur Verfügung.

Hindawi publishes peer-reviewed, Open Access journals across many areas of science, technology, and medicine, as well as several areas of social science. The Max Planck Society covers article-processing charges for Max Planck authors centrally. Further details are available on the MPDL website.

Catalog especially for graphic arts and prints.

The International Monetary Fund's eLibrary simplifies analysis and research with direct access to the IMF's periodicals, books, working papers and studies. Various statistical and visualization tools to showcase IMF datasets are offered free of charge via the IMF Data platform.

Nine Libraries belong to the Library Network at the World Bank Group and IMF Headquarters location in Washington D.C. References to materials owned by all the Libraries are available through JOLIS, the online catalog.

The Internet Archive is a non-profit organization that offers permanent access for the general public to historical collections that exist in digital format. The Internet Archive includes collections of digitized materials, including websites, software applications and games, music, movies and videos, moving images, and nearly three million public-domain books. The Internet Archive allows the public to upload and download digital material , but most of its data is collected automatically by its web crawlers to preserve as much of the public web as possible. The Wayback Machine, a huge web archive, contains over 150 billion web captures.

The Karlsruhe Virtual Catalogue (KVK) is a meta search engine which allows you to simultaneously access selected library and book trade catalogs worldwide. Altogether, these resources contain hundreds of millions of books, magazines and other media.

The KOBV-Index is a central database that is maintained and regularly updated at KOBV-Zentrale. Der KOBV-Index ist eine zentrale Datenbank, die in der KOBV-Zentrale gepflegt und regelmäßig aktualisiert wird.

Language Description Heritage (LDH) provides open access to descriptive material about the world's languages with a focus on traditionally difficult to obtain works. This collection is being compiled at first by the Max Planck Institute for Evolutionary Anthropology and now by the Max Planck Institute for the Science of Human History. -- Language Description Heritage (LDH) ist eine Datenbank, die freien Zugriff auf deskriptive Materialien zu den Sprachen der Welt gewährt. Dabei legt den Schwerpunkt auf überlicherweise schwer erhältlich Arbeiten. Die Sammlung wurde zuerst am Max-Planck-Institut für Evolutionäre Anthropology angelegt und wird nun am Max-Planck-Institut für Menschheitsgeschichte fortgeführt.

The Library of Congress Online Catalog is a database of books, serials, computer files, manuscripts, cartographic materials, music, sound recordings, and visual materials in the Library's collections.

LIVIVO bundles scientifically relevant resources from the subjects fields medicine, health, nutrition, environmental and agricultural sciences. It provides a common search interface over various data sources, such as library catalogs, specialist bibliographic databases, full texts from journals, and quality-controlled web content. LIVIVO combines the former ZB MED search portals MEDPILOT (2003 to 2015) and GREENPILOT (2009 to 2015).

MDPI (Multidisciplinary Digital Publishing Institute) is an academic open-access publisher with a portfolio of more than 400 peer-reviewed, multidisciplinary, open access, electronic journals. The Max Planck Society covers article-processing charges for Max Planck authors centrally. Further details are available on the MPDL website.

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).

In collaboration with authors and publishers, the National Center for Biotechnology Information (NCBI) provides free online access to books and documents in life science and healthcare.

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 OAPEN Library contains freely accessible academic books, mainly in the area of Humanities and Social Sciences. OAPEN works with publishers to build a quality controlled collection of Open Access books, and provides services for publishers, libraries and research funders in the areas of dissemination, quality assurance and digital preservation. OAPEN serves as delivery platform for various open access initiatives, including Knowledge Unlatched.

The Open Library of Humanities is an open access publishing platform, launched as an international network of scholars, librarians, programmers and publishers in January 2013. The OLH platform supports academic journals from across the humanities disciplines, as well as hosting its own multidisciplinary journal. Unlike many open-access publishers, the Open Library of Humanities does not charge individual author fees, but covers all costs by cooperating with an international library consortium.

PeerJ is an Open Access, peer-reviewed, scholarly journal. It considers and publishes Research Articles in the Biological and Medical Sciences. It aims for rapid decision making and will publish articles as soon as they are ready. PeerJ operates a 'Lifetime publishing plan' model. Unlike many Open Access publications which charge authors per publication, PeerJ provides low-cost publishing plans to individuals, which gives them lifetime rights to publish with PeerJ for free. The Max Planck Society covers the Enhanced Publication Plan for all Max Planck authors centrally. Further details are available on the MPDL website.