APO (Analysis & Policy Observatory) – Non-profit, open access platform for public policy research and other documents. Focus on Australia and New Zealand, but also with International sources.
BASE (Bielefeld Academic Search Engine) – Database of academic web resources with over 340 million documents indexed.
Eldis – Database of research on international development issues from over 8,000 publishers.
OpenGrey – Database of grey literature published in Europe; has been discontinued since 2020, however it is still possible to access the archive.
Pascal and Francis – An archive of the PASCAL and FRANCIS databases, which operated from 1972-2015. A wide range of literature types and subject areas, with focus on France and Europe.
These general databases may help you find repositories with datasets about a certain subject:
Registry of Research Data Repositories
You can also use general search engines like Google.com to search for data sets:
Some specific data sources that might be of interest:
Consortium of European Social Science Data Archives (CESSDA) – Social science data archives from across Europe.
European Data – Official portal for European data; contains data from the EU and also per EU member states, on a wide range of topics.
Inter-University Consortium for Political and Social Research (ICPSR) – International consortium of over 750 institutions; maintains a data archive of research from social and behavioural sciences.
UK Data Archive (UKDA) – The U.K.’s largest collection of social, economic, and population data.
UN E-Government Knowledgebase – Tool that allows for comparison of e-government development of U.N. member states.
Most systematic reviews can be found in academic databases, however you may find some here that are not (yet) published:
EPPI Centre (Evidence for Policy & Practice Information Centre) – Systematic reviews and evidence synthesis across many areas of social policy, including education, health, social care, developing economies, crime, environment, and sport.
OSF Registries – Search for preregistrations of systematic reviews or other studies.
PROSPERO – International database of prospectively registered systematic reviews in health and social care, welfare, public health, crime, justice, and international development where health is a related outcome.
EThOS – Database of doctoral theses from the U.K. [Note: database temporarily unavailable]
Networked Digital Library of Theses and Dissertations (NDLTD) (search here) – International organization promoting electronic theses and dissertations; also includes search engine.
Open Access Theses and Dissertations (OATD) – Database of open access graduate theses and dissertations from around the world. Currently contains over 7 million records.
Proquest Dissertations and Theses: Abstracts and Index – International, comprehensive collection of dissertations and theses. Radboud University has a subscription.
See here for a full list of open access disciplinary repositories, via the Simmons University Open Access Directory and also this list of Preprint repositories on Wikipedia.
bioRxiv – Preprint server for biology, including Neuroscience and some Psychology papers.
Cogprints – Multidisciplinary collection of self-archived papers from disciplines relevant to the study of cognition, including Psychology, Neuroscience, Linguistics, Computer Science, and Philosophy.
HAL – Multidisciplinary database of scientific output, including preprints and working papers, but also journal articles.
MediArXiv – Open archive for media, film, and communication studies.
MedRxiv – Preprints in the health sciences, including Health Economics, Health Policy, and Public and Global Health.
OSF Preprints – Large, multidisciplinary database, which aggregates preprints from other large databases including, e.g., bioRxiv, PsyArXiv. It may still be a good idea to search separately in non-OSF preprint databases because others such as bioRxiv and MedRxiv have more comprehensive search functions.
PsyArXiv – Preprints in the psychological sciences.
SocArXiv – Open archive of social sciences, which includes preprints, working papers, and published papers.
Conference Proceedings Citation Index (within Web of Science): This is usually checked off by default when searching in the Web of Science Core Collection. You can also use this tool to help you identify relevant conferences for your topic and later do a hand-search of the conference website.
Embase – Use Limits > Additional Limits > and filter by Publication Types to find Conference Papers and Reviews. Note: this link works only for students and employees of Radboud University; Connection with EduVPN is needed if working off-campus.
These databases are helpful for identifying clinical trials for which the results are not (yet) published.
ClinicalTrials.gov – Registry of U.S. and International clinical trials.
International Clinical Trials Registry Platform (ICTRP) – Portal provided by the World Health Organization (WHO), which gives access to trial registration provided by several international databases.
ISRCTN – International clinical trial registry