Open Access

Open Access (OA)  is the online, unrestricted access to peer-reviewed scholarly journal articles available to the readers free of charge.

Some of the leading Publishers providing OA articles are:
 
BioMed Central  is an STM (Science, Technology, and Medicine) publisher which has pioneered the open access publishing model

Public Library of Science (PLoS) is a nonprofit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource.

Bioline International is a not-for-profit scholarly publishing cooperative committed to providing open access to quality research journals published in developing countries.

Medknow publishersMedknow Publications (acquired by Wolters Kluwer Health) is a publisher for peer-reviewed, online/print+online journals in the area of STM. Medknow is the largest open-access publisher publishing on behalf of learned societies and associations. Medknow pioneers in 'fee-less-free' model of open access publishing and provides immediate free access to the electronic editions of the journals majority of which do not charge the author or author's institution for submission, processing, or publication of the articles.

Open J-Gate is a service by Informatics India Ltd dedicated to the promotion of the Open Access movement for scholarly journals. It provides 8588 Open Access Journals (5767 Peer-Reviewed).

Bentham Science Publishers publish over 230 peer-reviewed open access journals. These free-to-view online journals cover all major disciplines of science, technology, medicine, and social sciences.

Free Medical Journals

 OMICS Publishing Group is an Open Access publication model with a mission to influence, encourage and assist scientists that enables the dissemination of research articles to the global community. It provides an open forum to share on science and technology and research policies around the globe and contributes to the creation of an integrated space for science and technology.It also organizes meetings at the international level and this focus has successfully led to the expansion of the group into rising scientific areas and an ability to innovate, especially in the digital layout.

Open Access is the immediate (upon or before publication), online, free availability of research work without any of the restrictions on use commonly imposed by publisher copyright agreements.

Benefits:
 Open Access provides the means to maximize the visibility, and thus the uptake and use of research outputs, while works on the public domain are free from intellectual property rights whereas the use of OA articles requires proper attribution. 

In the current scholarly communications ecosystem, Open Access publishing practices are increasingly being adopted by institutions to provide access to scholarly materials such as theses, scholarly monographs, and book chapters to a wider academic community.

WHO Initiative:
Health Internetwork Access to Research Initiative (HINARI) provides free or very low-cost online access to the major journals in biomedical and related social sciences to local, not-for-profit institutions in developing countries. It was developed in the framework of the Health InterNetwork, introduced by the United Nations Secretary-General Kofi Annan at the UN Millennium Summit in the year 2000. It is a collaborative effort between the World Health Organization (WHO) and leading publishers of scientific journals. It aims to reduce financial and legal barriers to scholarship by providing Internet access to full–text research articles for scholars.

Digital Repositories

PubMed Central (PMC) is the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature. Launched in 2000 AD.

arXiv.org developed by Cornell University Library USA is an e-print service in the fields of physics, mathematics, non-linear science, computer science, quantitative biology, quantitative finance, and statistics.

The World Bank Open Knowledge Repository is the largest single source of development knowledge. It is The World Bank’s official open access repository for its research outputs and knowledge products.

Through the OKR, The World Bank collects, disseminates, and permanently preserves its intellectual output in digital form. The OKR is interoperable with other repositories and supports optimal discoverability and re-usability of the content by complying with Dublin Core Metadata Initiative (DCMI) standards and the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH).

Directory of Open Access Journals (Lund University Sweden) offers full-text access to quality controlled scientific and scholarly journals, covering several subjects and many languages.

HighWire, Stanford UniversityAs the leading ePublishing platform, HighWire Press partners with independent scholarly publishers, societies, associations, and university presses to facilitate the digital dissemination of journals, reference works, books, and proceedings.

JournalTOCs pulls together a database of Table of Contents (TOCs) from scholarly journals and provides a convenient single "one stop shop" interface to these TOCs

Max Plank Gesellschaft Germany

Institut National Santé et Recherche Médicale (INSERM)France

Welcome Trust United Kingdom

European Organization for Nuclear Research (CERN)Switzerland

Chinese Academy of Sciences China

SciDevNet

Indian Journals.com: Gateway to access, disperse and preserve knowledge

OAIster USA

 Directory of Open access Books is provided by OAPEN Foundation in cooperation with SemperTool

Creative Commons USA

eScholarship Repository the USA

Project Sherpa United Kingdom

Vidyanidhi (Meaning 'Treasure of Knowledge' in Sanskrit) is India's premier Digital library initiative to facilitate archival and access to doctoral theses.
Indian Academy of Sciences-publishes many open access journals-Current Science...
Article on OA
Open Access to the Scientific Journal Literature: Situation 2009

MIT OpenCourseWareMIT (OCW) is a web-based publication of virtually all MIT course content. OCW is open and available to the world and is a permanent MIT activity.
DSpace open source software enables open sharing of content that spans organizations, continents and time.
Eprints software by University of Southampton, UK
BASE is one of the world's most voluminous search engines, especially for academic open access web resources. The BASE is operated by Bielefeld University Library.

Publishing models in medical journals
Medical journals are published by scientific societies, university press, publishing agencies, and other for-profit or nonprofit organizations.

Association
Open Access Scholarly Publishers Association, OASPA

Open Access Button

Peter Suber,  Timeline of the OA Movement- Digital Access to Scholarship at Harvard University (DASH Repository)

Patrias K. Citing medicine: the NLM style guide for authors, editors, and publishers [Internet]. 2nd ed. Wendling DL, technical editor. Bethesda (MD): National Library of Medicine (US); 2007 -    [updated 2015 Oct 2; cited Year Month Day]. Available from: http://www.nlm.nih.gov/citingmedicine

OA policy is adopted by many publishers to offer free of charge access to the publications to the readers. This provision offer readers access to research papers without paying for an online journal subscription mainly.

Plan S......
DORA
Indian S&T OA Policy

Transformative agreements

Transformative agreements are those contracts negotiated between institutions (libraries, national and regional consortia) and publishers that transform the business model underlying scholarly journal publishing, moving from one based on toll access (subscription) to one in which publishers are remunerated a fair price for their open access publishing services. (Efficiency and Standards for Article Charges, ESAC)

Source:https://www.coalition-s.org/faq/what-is-a-transformative-agreement/

Ferwerda, Eelco, Mosterd, Tom, Snijder, Ronald, & Mounier, Pierre. (2021). UKRI Gap Analysis of Open Access Monographs Infrastructure. Zenodo. https://doi.org/10.5281/zenodo.5735021

Pastor-Ramon, E., Aguirre, O., García-Puente, M., María Morán, J. and Herrera-Peco, I., 2023. Sci-Hub use among Spanish researchers: Enemy or a learning opportunity for libraries?. Journal of Information Science, p.01655515221142432.