arXiv is an e-print service in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics. It provides access to more the 1.3 million e-prints. The Max Planck Society is a member institution of arXiv.

Each of the 371 databases of BioCyc describes the genome and metabolic pathways of a single organism. The BioCyc databases are divided into 3 tiers, based on their quality: Tier 1: 3 Databases, which have been created through intensive manual efforts and receive continuous updating: 1) *EcoCyc* describes the model organism Escherichia coli K-12. 2) *MetaCyc* describes metabolic pathways and enzymes for more than 1,500 organisms. 3) *BOCD* (BioCyc Open Compounds Database) is an open collection of chemical compound data from the BioCyc databases. BOCD includes metabolites, enzyme activators, inhibitors, and cofactors. Tier 2: 20 Databases, which were computationally generated and have undergone moderate curation. Tier 3: 349 Databases, which were also computationally generated, but have undergone no curation. Scientists can use the BioCyc Web site to visualize individual metabolic pathways or to view the complete metabolic map of an organism. The latter diagram can be used to analyze gene expression, proteomics, or metabolomics data, such as to produce animated views of time-course gene-expression experiments. The BioCyc Web site also provides genome browsing capabilities, and for the *EcoCyc* databases in particular, provides extensive information about transcriptional mechanisms of gene regulation.

BioMed Central is an STM (Science, Technology and Medicine) publisher of 270 peer-reviewed open access journals. The portfolio of journals spans all areas of biology, biomedicine and medicine and includes broad interest titles, such as BMC Biology and BMC Medicine alongside specialist journals, such as Retrovirology and BMC Genomics. The Max Planck Society is a BMC member and covers article-processing charges for Max Planck authors centrally. Further details are available on the MPDL website.

Cairn offers the most comprehensive collection of French and Belgian journals in social sciences available online. Note that access to newer content is generally not free of charge (moving wall 2 to 5 years).

CESSDA provides large scale, integrated and sustainable data services to the social sciences, having evolved from a network of European data service providers into a legal entity and large-scale infrastructure under the auspices of the European Strategy Forum on Research Infrastructures (ESFRI) Roadmap.CESSDA provides a seamless interface to datasets from social science data archives across Europe.

ChemSpider is a free chemical structure database providing fast text and structure search access to over 32 million structures from hundreds of data sources.

Cogitatio is an academic and community-oriented publisher based in Lisbon, which was founded in 2014 with the aim of promoting the open access dissemination of scientific knowledge. Cogitatio currently publishes 4 peer-reviewed Open Access journals focusing on research in the social sciences and humanities. From January 1, 2023, the Max Planck Society covers article-processing charges for Max Planck authors centrally. Further details are available on the MPDL website.

Welcome to CogPrints, an electronic archive for self-archive papers in any area of Psychology, neuroscience, and Linguistics, and many areas of Computer Science (e.g., artificial intelligence, robotics, vision, learning, speech, neural networks), Philosophy (e.g., mind, language, knowledge, science, logic), Biology (e.g., ethology, behavioral ecology, sociobiology, behaviour genetics, evolutionary theory), Medicine (e.g., Psychiatry, Neurology, human genetics, Imaging), Anthropology (e.g., primatology, cognitive ethnology, archeology, paleontology), as well as any other portions of the physical, social and mathematical sciences that are pertinent to the study of cognition.

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.

"Data Services for the Social Sciences" is a department of GESIS - Leibniz Institute for the Social Sciences. Its mission is to foster FAIR data, open science and reproducible research in the quantitative and computational social sciences. To ensure that data holdings remain usable and interpretable over the long term, it offers sustainable infrastructures and services for data management, curation, and long-term preservation. ​These include archiving services with different curation levels for different needs as well as access to archived data including access to sensitive data in the GESIS Secure Data Center. The services also cover the data registration agency da|ra and training on data management for easier retrieval and re-analysis of data.

Dataset Search lets you find datasets wherever they’re hosted, whether it’s a publisher's site, a digital library, or an author's personal web page.

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.

The Digital Library of the Commons (DLC) is a gateway to the international literature on the commons. The DLC provides free and open access to full-text articles, papers, and dissertations. This site contains an author-submission portal; an Image Database; the Comprehensive Bibliography of the Commons; a Keyword Thesaurus, and links to relevant reference sources on the study of the commons.

EconBiz - a suject portal for economics and business studies - supports you in retrieving economic literature. It offers a literature search across important German and international databases, including the holdings of ZBW, and provides access to information services of libraries. EconBiz - die Virtuelle Fachbibliothek Wirtschaftswissenschaften - unterstützt Sie bei der Recherche wirtschaftswissenschaftlicher Fachinformationen. Sie können in Internetquellen, in Online-Katalogen und Volltexten recherchieren und auf Informationsdienstleistungen von Bibliotheken zugreifen. Enthält neben aktueller Literatur viele Publikationen , die für Wirtschaftshistoriker interessant sind (1500 ff).

The Library of Economics and Liberty is dedicated to advancing the study of economics, markets, and liberty. The books and essays on this website represent classics of economic thought, both historical and modern.•Authoritative editions of classics in economics, and related works in history, political theory and philosophy. Contains also blogs, talks and essays.The Library of Economics and Liberty carries the popular Concise Encyclopedia of Economics, edited by David R. Henderson.

EconStor is the 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.

EMBL-EBI maintains the world’s most comprehensive range of freely available and up-to-date molecular databases. Developed in collaboration with institutions worldwide, the EMBL-EBI services let you share data, perform complex queries and analyse the results in different ways. You can work locally by downloading the data and software, or use the web services to access EMBL-EBI resources programmatically.

Eurostat is the statistical office of the European Union and its homepage offers a whole range of data that governments, businesses, the education sector, journalists and the public can use for their work and daily life. The data covers following themes: - General and regional statistics - Economy and finance: National accounts (including GDP), ESA Input-Output tables, European sector accounts, Pensions in National Accounts, Government finance and EDP, Exchange rates, Interest rates, Harmonised Indices of Consumer Prices (HICP), Housing price statistics, Purchasing Power Parities (PPPs), Balance of payments - Population and social conditions - Industry, trade and service: Manufactured goods (Prodcom), Postal services, Structural business statistics, Short-term business statistics, Tourism - Agriculture and fisheries - International trade - Transport - Environment and energy - Science and technology