ArXiv the most popular open source archive of essays and full texts of scientific publications, created on the basis of the library of the Cornell University. It contains over 684,000 electronic publications in physics, mathematics, computer science, biology, finance and statistics.

Cogprints open archives on psychology, neurology, biology, linguistics, philosophy and medicine (psychology, psychiatry, neurology, genetics), anthropology (primateology, cognitive ethnology, archeology, paleontology) and computer sciences (artificial intelligence, robotics, neural networks); as well as from other physical, social and technical sciences.

COPAC Union Catalogue (United Kingdom) a directory of 22 most trusted university libraries in Britain and Ireland, as well as the British Library. Works on Z39.50 protocol. There are three search options available: by author and title, by subject area and by search of periodicals. All interfaces are simple and convenient. In the results list, you can view the full record and / or mark it for further storage. The service functions include the ability to upload results to the specified e-mail address. The disadvantage of this directory is typical for most directories that run under Z39.50: the results include a large number of duplicate entries per publication, from databases of various libraries.

The Directory of Open Access Repositories (OpenDOAR) search for reliable scientific information in open repositories around the world, supported by the SHERPA service at the University of Nottingham. Provides opportunities for searching scientific materials in various fields of knowledge in more than 2 600 e-archives.

E-Books Directory search for reliable scientific information in open repositories around the world, supported by the SHERPA service at the University of Nottingham. Provides opportunities for searching scientific materials in various fields of knowledge in more than 2 600 e-archives.

Elektronische Zeitschriftenbibliothek (EZB) the library of electronic journals since 1997, within the framework of the project of the University Library of Regensburg, in cooperation with the Library of Munich Technical University, offers quick, structured and unified access (in English and German) to scholarly full-text journals. It contains 76 419 titles, of which 13,923 journals from all fields of knowledge are issued only in electronic form. 45,575 titles of journals are freely available in full-text version. All institutions have full access to all publications in the project.

Figshare a repository that allows you to upload, store and share research results openly.

Hikari is the publisher of international journals and books on science, technology, mathematics, medicine and economics. The Hikari logs are archived by the digital preservation service, whose purpose is to preserve scientific literature and ensure long-term access to electronic archives. Hikari is a member of the International Association of Publishers Association (Crossref) and co-founder of ICORE.

Open J-Gate an electronic library of scientific journals on social, humanitarian, natural sciences and engineering, supported by Informatics India Ltd. Currently includes more than 6300 names of magazines, organized in the fields of knowledge. Document search is carried out by author, title, keywords, date of publication.

Open Library a site that aims to create a catalog of books that have ever been published. Works on the principle of Wikipedia - the creation of a separate page for a separate book by the users themselves. In addition to the catalog of books, the resource provides free access to e-books (today - more than 1 million names).

Open Textbooks Library access to the open source library of free, peer-reviewed, and licensed textbooks.

Registry of Open Access Repositories (ROAR) a register of all repositories and other sources of open information all over the world. The project is developed by the University of Southampton (UK) and is part of the network.

Scribd a social service that allows anyone on the Internet to easily publish, distribute and share e-books, documents, presentations, newsletters, and more. Documents from Scribd are displayed in a special flash module, which can also be embedded on any page (for example, blogs) using the HTML code provided by the service.

The Free Library founded in 2003, the resource offers free full-text versions of classical literary works from hundreds of well-known authors, biographies, and images. Recently, the Free Library has been expanded to include a massive collection of periodicals from hundreds of leading publications on business and finance, communications, culture, health, humanities, law, politics, technology and the social sciences.

Наукова електронна бібліотека періодичних видань НАН України is an open access library and provides free access for readers to scientific information on the Internet with the right to read, download, copy, distribute, print, search, refer to full-text articles, index, ie use it with a legitimate purpose without financial, legal and technical obstacles. Current status - more than 6 500 titles of editions.

Наукова періодика України – the portal of the scientific periodicals of the National Library of Ukraine to them. VI Vernadsky National Academy of Sciences of Ukraine presents open access to scientific journals and collections of scientific works published in Ukraine, contains more than 35 000 titles of editions.

Baidu (кит. 百度 (Bǎidù), Байду, NASDAQ: BIDU) a leader among Chinese search engines. By the number of queries, the search site "Baidu" ranks 3rd in the world (3 billion 428 million, with a share in the global search 5.2%).

BASE (Bielefeld Academic Search Engine) (Germany) one of the world's largest search engines, specialized in finding scientific documents for open access on the Internet. Operator BASE is a library of the University Bielefeld (Germany). BASE collects, normalizes and indexes data from repository servers using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). In addition to the OAI metadata, BASE indexes selected web sites and local library data. All this together can be searched through one interface.

CiteSeerХ the search engine is focused on the publication of computer and information technology, although there are also materials from other industries. CiteSeerX not only finds resources in free access, but also serves as an electronic library. That is why the key words here are often found and downloaded in full.

DuckDuckGo the site provides an open source search engine that uses information from many sources to deliver accurate and varied results. Compliance with the policy of full privacy – refusal to collect, store and process user data.

FreeFullPDF a search engine for electronic resources in the fields of medicine, biology, chemistry, physics, materials science and economics. Provides access to more than 80 million scientific articles, patents for free access.

Google Scholar a search engine that indexes the full text of scientific publications of all formats and disciplines. Google Scholar includes articles published in magazines, stored in repositories or located on research sites or individual scholars.

Google Books is a full-text search service for books digitized by Google (over 10 million books from the largest US libraries). The library offers millions of great editions with which you can read or read them completely for free.

Metasearch Search Engine search service (operating since 1998) in more than 300 world magazines and publications in the field of management, economics, computer science, technology, education, sports, art, etc.

Microsoft Academic Search a research portal from Microsoft Corporation that was developed to explore the links between scientists, researchers, students and their research.

RefSeek search engine for students and researchers, searches through web pages, books, encyclopedias, magazines and newspapers.

Science.gov a search engine that covers more than 60 databases and over 2200 individual sites from 15 federal agencies that offer 200 million pages of information from US authoritative research institutions, including research and development.

ScienceResearch.com a scientific search engine that performs a full-text search in the magazines of many major publishing houses (Elsevier, Highwire, IEEE, Nature, Taylor & Francis, etc.). Searches for articles and documents in open scientific databases: Directory of Open Access Journals, Library of Congress Online Catalog, Science.gov, Scientific News.

WorldWideScience.org a global scientific search engine that searches for information on national and international scientific databases and portals.

Yahoo English-language search engine that has the most developed directory structure and various services. Hundreds of thousands of different Internet resources are arranged in 14 main sections, each of which has several sub-sections with more narrow themes.

Academia.edu is a social network for the cooperation of scientists. The network can be used to share with other articles, keep track of their quotes, and keep track of news of research and development by names and keywords. It is positioned as a universal network for representatives of all spheres of science.

ResearchGate is a social network, oriented mainly to the representatives of natural and exact sciences.

Prometheus is a public project for mass open online courses (IWC). Free online access to the best university level courses.

ВУМ online an educational project that disseminates ideas and promotes the development of civil society in Ukraine. Courses from leading professors of business schools, the public sector, practitioners in business and social affairs.

World Intellectual Property Organization (WIPO) a specialized UN agency created to encourage creativity and protect intellectual property around the world.

INCOSE nonprofit organization, an international council for system engineering, which aims to develop system engineering and professional growth of system engineers.

Internet Society (ISOC) community of the Internet. A nonprofit professional organization for the development of the Internet, coordinates administrative activities.

Internet Engineering Task Force (IETF) international nonprofit association on current issues of technical and organizational problems on network standards.

Internet Research Task Force (IRTF) – the research group is an international nonprofit association for the development of technologies of the future.

ICANN – Internet Corp.for Assigned Names and Numbers an international association of researchers, developers and manufacturers of network solutions for addressing the Internet address space.

Network Information center (InterNIC) the general name of the providers of registration, information and databases on the Internet; the organization responsible for providing information about the network.

IANA – Internet Assigned Number Authority the international administration of the address space for the assignment of addresses, the registration of top-level domains.

International Electrotechnical Commission (IEC) an international standardization organization in the field of electrical, electronic and related technologies.

Міжнародне агентство з атомної енергії (МАГАТЕ) a universal center for promoting international cooperation in the peaceful uses of nuclear energy.

International Energy Agency (IEA) an autonomous international body within the Organization for Economic Cooperation and Development (OECD).

The Organization of the Petroleum Exporting Countries (OPEC) a cartel created by the oil-producing states to stabilize oil prices. The members of this organization are the countries whose economy depends on the income from oil exports.