Bielefeld Academic Search Engine BASE [Link]
BASE is one of the world's most voluminous search engines especially for academic web resources. BASE provides more than 240 million documents from more than 8,000 content providers. You can access the full texts of about 60% of the indexed documents for free (Open Access). BASE is operated by Bielefeld University Library.

Cite Factor [Link]
Citefactor is a service that provides access to quality controlled Open Access Journals. The Directory indexing of journal aims to be comprehensive and cover all open access scientific and scholarly journals that use an appropriate quality control system, and it will not be limited to particular languages or subject areas.

Crossref [Link]
Crossref makes research outputs easy to find, cite, link, assess, and reuse. We’re a not-for-profit membership organization that exists to make scholarly communications better. We rally the community; tag and share metadata; run an open infrastructure; play with technology; and make tools and services—all to help put scholarly content in context.

Dimensions [Link]
Dimensions covers millions of research publications connected by more than 1.5 billion citations, supporting grants, datasets, clinical trials, patents and policy documents.

Directory of Research Journals Indexing [Link]
DRJI provides ready access to education literature to support the use of educational research and information to improve practice in learning, teaching, educational decision-making, and research. Directory of Research Journals Indexing is a free online service that helps you to find web resources for your articles and research.

Eurasian Scientific Journal Index [Link]
The ESJI provides indexing of major international journals and proceedings. Author can get information about international journal impact factor, proceedings (research papers) and information on upcoming events. All the journal pages have pointers to Web pages of the publishers which are integrated into the ESJI stream pages.

Index Copernicus World List [Link]
The growing interest in the ICI Journals Master List database, the number of applications and the number of journals which had not met the criteria required for the indexation, have inspired us to create a global database of scientific journals the ICI World of Journals. 

Journal Factor [Link]
Journal Factor is a globally recognized forum for promoting your research work and knowledge sharing as we know research is all about communication. It's always difficult to know what the impact factor of your work is going to be. Sometimes what we consider creative is not that something really determines creativity which has published over the period of time.

Lens [Link]
The Lens Collective Action Project levels the playing field with universal and equitable access to open innovation knowledge. The Lens focuses on illuminating what innovation capabilities exist, who and which institutions have them, and how those capabilities fit into the complex jigsaw puzzle of problem solving.

OpenAIRE [Link]
OpenAIRE’s mission is closely linked to the mission of the European Commission: to provide unlimited, barrier free, open access to research outputs financed by public funding in Europe. OpenAIRE fulfils the EOSC vision substantially, as its operations already provide the glue for many of the user and research driven functionalities, whether these come from the long tail of science (repositories and local support) or domain disciplined research communities or Research Infrastructures.

Open Ukrainian Citation Index [Link]
The OUCI is intended to simplify the search for scientific publications, to attract editorial attention to the problem of completeness and quality of the metadata of Ukrainian scholarly publications, and will allow bibliometrics to freely study the relations between authors and documents from various disciplines, in particular in the field of social sciences and humanities.

ResearchGate [Link]
ResearchBib is open access with high standard indexing database for researchers and publishers. Research Bible may freely index journals, research papers, call for papers, research position.

ROAD Directory of Open Access Scholarly Resources  [Link]
The CIEPS, also known as the ISSN International Centre, is an intergovernmental organization which manages at the international level the identification and the description of serial publications and ongoing resources, print and online, in any subject.

ScienceGate Academic Search Engine [Link]
Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery.

Scientific Indexing Services (SIS) [Link]
Scientific Indexing Services (SIS) was founded by renowned scientists. A group of 70 scientist from various countries in different disciplines are started SIS with specific objective of providing quality information to the researcher. SIS offering academic database services to researcher.

Scilit [Link]
Scilit is a comprehensive, free database for scientists using a new method to collate data and indexing scientific material. Our crawlers extract the latest data from CrossRef and PubMed on a daily basis. This means that newly published articles are added to Scilit immediately.

Scite_ [Link]
scite is an award-winning platform for discovering and evaluating scientific articles via Smart Citations. Smart Citations allow users to see how a publication has been cited by providing the context of the citation and a classification describing whether it provides supporting or contrasting evidence for the cited claim.

Semantic Scholar [Link]
Semantic Scholar is and always will be open and free for all to use. In addition to the search and discovery tools available at semanticscholar.org, we provide the Semantic Scholar API and Open Research Corpus as free services to the research community.

WorldCat [Link]
WorldCat is a union catalog that itemizes the collections of 17,900 libraries in 123 countries and territories that participate in the OCLC global cooperative. It is operated by OCLC, Inc.The subscribing member libraries collectively maintain WorldCat's database, the world's largest bibliographic database. The database includes other information sources in addition to member library collections.