PubMed comprises over 29 million citations for biomedical literature from MEDLINE, life science journals, and online books. PubMed citations and abstracts include the fields of biomedicine and health, covering portions of the life sciences, behavioral sciences, chemical sciences, and bioengineering. PubMed also provides access to additional relevant web sites and links to the other NCBI molecular biology resources. PubMed is a free resource that is developed and maintained by the National Center for Biotechnology Information (NCBI), at the U.S. National Library of Medicine (NLM), located at the National Institutes of Health (NIH).

The Russian national bibliography is going back to 1998 and consists of 8 series: * Knigi Rossii (formerly Knizhnaia letopis’): Russian book publications. * Statii iz rossiiskikh gazet (formerly Letopis’ gazetnykh statei): Bibliographic entries on documentary materials, articles, and works of fiction from every major newspaper in Russia. * Statii iz rossiiskikh zhurnalov (formerly Letopis’ zhurnal’nykh statei): The complete index to Russian journals. * Retsenzii iz rossiiskikh izdanii (formerly Letopis’ retsenzii): Book reviews (Russian and foreign) found in the central and regional Russian press. * Rossiiskie kartograficheskie izdaniia (formerly Kartograficheskaia letopis’): Bibliographic information for all cartography and maps produced in Russia. * Avtoreferaty dissertatsii (formerly Letopis’ avtoreferatov dissertatsii): Indexes all synopses of dissertations defended in research and educational establishments in the Russian Federation. * Rossiiskie notnye izdaniia (formerly Notnaia letopis’): General index to Russian music. * Rossiiskie izoizdaniia (formerly Letopis’ izoizdanii): Bibliographic index of albums, posters and reproductions published either separately or appearing in books, collected works and magazines.

The SAO/NASA Astrophysics Data System (ADS) is a digital library portal for researchers in astronomy and physics, operated by the Smithsonian Astrophysical Observatory (SAO) under a NASA grant. The ADS maintains three bibliographic databases containing more than 13 million records covering publications in Astronomy and Astrophysics, Physics, and the arXiv e-prints. Abstracts and full-text of major astronomy and physics publications are indexed and searchable through the new ADS modern search form as well as a classic search form.

The research database "Scholarly Journals and Newspapers in the Age of Enlightenment", conducted by the Göttingen Academy of Sciences, provides an extensive systematic index to German-language periodicals of the 18th century. It is based on the long-term research project "Scholarly Journals and Newspapers", which besides indexing and digitizing these scholarly journals aims to visualize their significant role for the emergence and structures of the "Enlightened scientific community". The project focuses on interdisciplinary journals, comprising of original contributions, book reviews, scholarly news as well as all facets of critique. The interactive online database also includes the data of the two previous research projects "Index of German-language Periodicals" (IdZ 18) and "Systematic Index of German-language Review Journals" (IdRZ 18). By the year 2025, it will give access to 323 periodicals (ca. 2,775 volumes and ca. 1,260,000 pages), spanning the time period 1688-1815.

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.

Sciwheel is an advanced reference management system that provides assisting tools for discovery of research works, reading, annotation, as well as scientific and collaborative writing. It features a web-based application, a browser extension, citation tools for Microsoft Word and Google Docs, and a mobile application.

Scopus is a large abstract and citation database of peer-reviewed literature, including scientific journals, books and conference proceedings, covering research topics across all scientific and technical disciplines, ranging from medicine and social sciences to arts and humanities. Further, with smart tools totrack, analyze and visualize research, Scopus empowers you to advance your science beyond the text.

Springer Nature publishes the largest available collection of reproducible laboratory protocols and methods for the life sciences. The Experiments platform provides accees to the content from SpringerProtocols, Nature Methods, Nature Protocols and Protocol Exchange through a single easy-to-use platform, designed to save researchers' time.

In addition to the 75.000 prints belonging to the basic content, VD16 comprises a supplement of more than 25.000 new titles. New titles are added continuously through acquisitions by the Bayerische Staatsbibliothek for the Collection of German Prints, as well as through data provided by national and foreign libraries.

The bibliographic project, Bibliography of Books Printed in the German Speaking Countries from 1601 to 1700 (VD17), intends to establish a German National Bibliography of the 17th century imprints. All German titles and all titles which have been printed or published in the former German speaking countries will be catalogued. Broadsheets are listed, musica practica (notations) and maps are excluded. VD 17 will be continuously enlarged and made more complete by contributions from associated libraries, the database currently contains more than 300.000 entries.

The Web of Science™ Core Collection provides researchers with access to the world's leading bibliographic and citation databases. Authoritative, multidisciplinary content covers over 12,000 of the highest impact journals worldwide, including Open Access journals, as well as over 150,000 conference proceedings and more than 50,000 editorially selected books. You'll find current and retrospective coverage in the sciences, social sciences, arts, and humanities, with coverage back to 1900. A unique feature of the WoS is that from any bibliographic record in the database links are available to its cited references, to related articles and to citing articles. In some instances additional links (e.g. to the journal impact factor) may also be available.

wiso is an online database specially tailored to the needs of users from academic and research institutions by GBI-Genios. It aggregates mainly German content from various publishers, covering economics, social sciences, psychology and technology. wiso provides access to major reference databases, to full texts of selected journals, e-books, magazines and newspapers like VDI Nachrichten or Handelsblatt as well as to company information and market data.

zbMATH Open (formerly known as Zentralblatt MATH) is the world's most complete and longest running abstracting and reviewing service in pure and applied mathematics. The MATH Database contains several million entries drawn from more than 3,500 serials and journals, and more than 1,100 book series and monographs. The entries are classified according to the Mathematics Subject Classification Scheme (MSC 2000).

Zoological Record provides access to publications in animal biology and biodiversity. It covers 5,000 serials, plus many other sources of information, including books, reports, and meetings. It contains, in particular, a significant amount of literature on insects, reptiles, birds, fish and wildlife which is not included elsewhere (e.g. in BIOSIS Previews). It is also a leading taxonomic reference work.