CORE’s mission is to aggregate all open access research outputs from repositories and journals worldwide and make them available to the public. In this way CORE facilitates free unrestricted access to research for all. We offer seamless access to millions of open access research papers, enrich the collected data for text-mining and provide unique services to the research community. CORE is providing a free API.

Data Europa EU is a central point of access to European open data from international, European Union, national, regional, local and geodata portals. The official portal for Euopean data consolidates the former EU Open Data Portal and the European Data Portal. Data Europa EU gives access and fosters the reuse of European open data among citizens, business and organisations. The portal promotes and supports the release of more and better-quality metadata and data by the EU’s institutions, agencies and other bodies, and European countries, enhancing the transparency of European administrations. Furthermore, it is intended to educate citizens and organisations about the opportunities that arise from the availability of open data. Currently, Data Europa EU contains more than 1.5 million European public sector datasets grouped by over 180 catalogues and pertaining to different topical categories.

Digi20 concentrates on the digitalization of monographs published in the second half of the 20th century, predominantly in the field of humanities and social sciences. In the first phase of the project, approx. 4,700 titles of programme segments of the publishers Vandenhoeck & Ruprecht, Wilhelm Fink / Ferdinand Schöningh as well as Otto Sagner were digitized. In a second phase, further approx. 1,750 titles are being included till 2014 by consecutively digitizing all monographs up to a defined ‘Moving Wall’ of three to five years to the current year of publication.

Since its foundation in 1964 the Max Planck Institute for European Legal History has been intensively engaged in research into the history of private law in Europe. It therefore has a particularly rich store of literary sources on 19th century German, Austrian and Swiss private and civil procedural law. With support from the German Research Foundation (DFG) it has been possible to digitize this exceptional concentration of material and make it available to a wider scientific audience. In the course of the project, which extended from 1997 until 2002, some 4,316 volumes were digitized comprising around 1,350,000 pages. For the Institute library this venture into digitization represents a continuation of its long-standing initiative to maintain and conserve its collections.

The primary aim of DOAB is to increase discoverability of Open Access books. Academic publishers are invited to provide metadata of their Open Access books to DOAB. An overview of participating publisher can be found here.

Edition Open Access provides open access to the publications of the Max Planck Research Library for the History and Development of Knowledge. The aim is to disseminate the results of scholarly work – in accordance with the open-access paradigm – to a broad audience rapidly and at low cost. The volumes presented here are directed at scholars and students in a wide range of disciplines. The works are available online both as print-on-demand books and open-access publications and can be accessed, together with additional information.

Google Book Search is a service from Google that searches the full text of books that Google scans, converts to text using optical character recognition, and stores in its digital database.

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.

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.

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.

MIA contains the writings of 592 authors representing a complete spectrum of political, philosophical, and scientific thought, generally spanning the past 200 years. Being a communist means working for the self-emancipation of the working class; it means striving to unite the working class, in all its diversity, in the struggle to overthrow capitalism. In the 1840s, Marx and Engels placed communism on a scientific footing through the theory of dialectical materialism. Marxists are those who have continued this ever since. If any one of the following criteria apply, the MIA Collective may decide to place the writer into the Reference Archive: (i) they pre-date Marx and Engels, (ii) they specifically reject Marxism, (iii) their work is practically and theoretically unconnected or hostile toward the workers movement, (iv) their work is idealistic or lacking in dialectic. Where a writer contributes to Marxist theory and practice for a part of their life, while other works lie outside of Marxism, then the whole of their writing will be placed in the Marxist Writers' Archive.Contains: Karl Marx/ Friedrich Engels - Werke ; Rosa Luxenburg; August Bebel; Antonio Gramsci ...

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

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.

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