Grey literature sources

Librarians from Oxford Health library service have compiled this list to support literature searches of pieces that might not be found in other healthcare databases.

Click on each section to find the list for each category.

You can find guides and tutorials on how to search grey literature and how to evaluate grey literature sources in our critical appraisal guides and tutorials page.

Charitable sources

Charitable and think tank sources

Age Info Information resource provided by the Centre for Policy on Ageing Library Service, covering social gerontology.
Charity Choice Charity directory and fundraising website with a list of all UK
registered charities
Kings’ Fund The King’s Fund Database is the online catalogue of The King’s Fund Library Service. Subjects include health and social care management and policy, systems, services and leadership. Coverage is from 1863 to present
NESTA UK agency for innovation
NSPCC Database for safeguarding, child protection, child abuse and neglect
Nuffield Trust The Nuffield Trust is an independent health think tank. Publications are available to download.
RAND RAND produce reports on a range of public health topics, freely available as eBooks. You can search over 20,000 RAND publications dating back to 1946, and filter by theme.
The Health Foundation The Health Foundation is an independent health think tank. Publications are available to download. Hard copies of many publications can also be ordered free of charge.
Clinical trials and systematic reviews

Clinical trials and systematic reviews

CenterWatch Worldwide database of registered clinical trials. A registry of clinical trials in the US
ICTRP Search Portal A searchable registry of clinical trials from all around the world
ISRCTN (International Standard Randomised Controlled Trial Number) Registry A primary clinical trial registry recognised by WHO and ICMJE that accepts all clinical research studies (whether proposed, ongoing or completed), providing content validation and curation and the unique identification number necessary for publication. All study records in the database are freely accessible and searchable.
NICE Local Practice Case Studies A collection of over 500 working examples of quality improvement in health and social care services
PROSPERO is an international database of prospectively registered systematic reviews in health and social care, welfare, public health, education, crime, justice, and international development, where there is a health related outcome
ScanMedicine 11 clinical trials databases from across the world can be searched simultaneously.
UK Clinical Trials Gateway  A searchable database of non-commercial clinical trials
Data repositories

Data repositories

European data Open data research repository created by CERN and OpenAIRE to enable the sharing, curation and publication of data and software.
Find open data UK government Data published by central government, local authorities and public bodies.
Office for National Statistics (ONS) The UK’s largest independent producer of official statistics and statistical bulletins, and the recognised national statistical institute of the UK.
OpenAire A comprehensive and open dataset of research information
Oxford Population Health Data sets from Health Economics Research Centre (HERC)
Zenodo Provides access to open data published by EU institutions and bodies.


Evidence for Policy and Practice Information Centre The databases give access to full references for primary data studies on which our research synthesis is based along with a basic description of study characteristics.
International Health Technology Assessment Database The International Health Technology Assessment Database has been relaunched, and provides free access to bibliographic information about ongoing and published health technology assessments commissioned or undertaken by HTA organisations from around the world.
Policy Commons Policy Commons is a public policy database launched in November 2020. It contains documents from think tanks, IGOs, NGOs, and research centers. Some documents are archived from inactive organizations. you may need to register for a free account to access.
TripDatabase  Trip is a clinical search engine, but as well as research evidence, it also provides a gateway to other content types, including images, videos, patient information leaflets, educational courses and news. (Use your OpenAthens account for Pro version)
Dissertations and thesis

Dissertations and thesis

DART-Europe E-theses Portal A partnership of research libraries and library consortia working together to improve access to European research theses.
National Digital Library of Theses and Dissertations (NDLTD) International Thesis and Dissertations aims to be the best possible resource for finding open access graduate theses and dissertations published around the world.
Government sources

Government sources

Department of Health, UK Publications, reports, policies and other information from
the Department of Health.
GOV.UK Website for the UK Government with a search facility for government publications.
Hospital Episode Statistics (HES) Hospital Episode Statistics (HES) is a curated data product containing details about admissions, outpatient appointments and historical Accident and Emergency attendances at NHS hospitals in England.
House of Commons Library Information and analysis on legislation, policy areas and topical issues
National Archives Official archive and publisher for the UK government and guardians of over 1,000 years of iconic national documents. This is a non-ministerial government department which is a cultural, academic and heritage institution with expert advisers in information and records management.
National Institute for Healthcare Excellence(NICE) Independent organisation providing national guidance on promoting good health / preventing ill health. NICE produce clinical guidance on Public Health, Health Technologies and Clinical Practice.
NHS England – Transformation Directorate Website for the Transformation Directorate at NHS England, driving the digital transformation of the NHS and social care.
Statistics at DHSC Statistics published by the Department of Health and Social Care (DHSC).
UK Health Security Agency (UKHSA) Grey Literature: index and alternative sources and resources This list has been compiled to help librarians and researchers, particularly in Public Health, to find resources that fall into this category and flag up alternative sources for queries not easily resolved by the clinical / medical database model.
Medical and health sciences preprints

Preprints services

ASAPbio (Accelerating Science and Publication in biology)maintains a list of preprints services.
Authorea: Open Research Collaboration and Publishing Health and sciences preprints
F1000Research Open Research publishing platform for scientists, scholars and clinicians offering rapid publication of articles and other research outputs.
medRxiv  is a free online archive and distribution server for complete but unpublished manuscripts (preprints) in the medical, clinical, and related health sciences.
Research Square Author services company in medical and allied health sciences
SSRN The Social Science Research Network is a repository for preprints devoted to the rapid dissemination of scholarly research in the social sciences, humanities, life sciences, and health sciences, among others.
Search engines

Search Engines

BASE: Bielefeld Academic Search Engine A search engine especially for academic web resources. It includes only document servers that comply with the specific requirements of academic quality and relevance. It aims to locate web resources of the “Deep Web”, which are ignored by commercial search engines or get lost in the vast quantity of hits.
Carrot2 Carrot² is an open source search results clustering engine. It can automatically cluster small collections of documents.
Dogpile A metasearch engine for information on the World Wide Web that fetches results from Google, Yahoo! and Yandex, and includes results from several other popular search engines, including those from audio and video content providers.
DuckDuckGo The search engine that doesn’t track you. Allegedly a superior search experience with smarter answers, less clutter and real privacy.
Google Advanced Search Search for words appearing on specific websites and/or specific file types — very useful for finding reports, datasets and similar types of material.
Mednar Mednar is a free, medically-focused deep web search engine.
OpenMD A search engine for health information. Includes documents from government agencies, global health organizations, medical journals, and reference sites.
Semantic Scholar A free, AI-powered research tool for scientific literature.

Page last reviewed: 19 March, 2024