Deutsche Digitale Bibliothek
The aim of the German Digital Library (DDB) is to give everyone free access to Germany's cultural and scientific heritage via the Internet, i.e. to millions of books, archival materials, pictures, sculptures, pieces of music and other sound documents, films and sheet music. As a central, national portal, the DDB is intended to network the digital offerings of all German cultural and scientific institutions.
Bielefeld Academic Search Engine (BASE)
A multidisciplinary, scientific search engine for bibliographical data of document servers worldwide, selected web sites and local data collections. In some cases, BASE allows a full-text search.
Directory of Open Access Books (DOAB)
The Directory of Open Access Books (DOAB) lists over 10.000 peer-reviewed e-books from 247 academic publishers, wich are freely accessible in full text. (12/2017)
EconStor is the new Open Access server of the German National Library of Economics – Leibniz Information Centre for Economics. EconStor provides a basis for the free publication of academic literature in economics. Any research facility wishing to publish and permanently preserve relevant publications in economics under the terms of Open Access can do so on EconStor.
EU Bookshop is an online service giving access to the publications of the institutions and other bodies of the European Union. A lot is offered free of charge. Many publications are available in PDF format.
National / Alliance licenses for electronic media
Since 2004 the DFG (German Research Foundation) is financing national licences for databases, digital collections and electronic journals in order to improve access to electronic resources for German universities, research establishments and research libraries.
The databases activated for the WZB can be found here https://www.wzb.eu/de/literatur-daten/suchen-finden/fachdatenbanken.
Open Access Publishing in European Networks (OAPEN)
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.
Research Papers in Economics (RePEc)
RePEc is a collaborative effort of hundreds of volunteers in 75 countries to enhance the dissemination of research in economics and related sciences. The heart of the project is a decentralized bibliographic database of working papers, journal articles, books, book chapters and software components, all maintained by volunteers. The collected data is used in various services, e.g. IDEAS (the complete RePEc database), EDIRC (Institutions) and CitEc (citation analyis).
SocArXiv, open archive of the social sciences, provides a free, non-profit, open access platform for social scientists to upload working papers, preprints, and published papers, with the option to link data and code. SocArXiv is dedicated to opening up social science, to reach more people more effectively, to improve research, and build the future of scholarly communication.
Social Science Open Access Repository (SSOAR)
SSOAR provides social science publications, for free, available with full texts. Its goal is to implement the "green road" to open access by providing users with free electronic access to pre-prints and post-prints of publications.
Social Science Research Network (SSRN)
Comprehensive collection of Papers (ca. 388,604) related to the whole research field of economics. By creating an account (for free), you can easily share and revise your research; view and download the latest research in your field (My Briefcase).
Wikisource collects and stores in digital format previously published texts; including novels, non-fiction works, letters, speeches, constitutional and historical documents, laws and a range of other documents. All texts collected are either free of copyright or released under a free license. Wikisource is provided by the Wikimedia Foundation.