The DOAJ provides full-text access to over 10,000 scholarly journals and over 1 million articles. It provides free access to articles in all science fields. The database also contains articles in all languages and from all scientific communities. Journals are sorted by topic or alphabetical order. Running a search for a particular article in a journal is possible for approximately 5,000 journals. For the other journals, you can run a search by Issue number on the publisher’s website.

Web platform created in 2006 for accessing academic and professional OA journals (3000+ journals). You can run searches in journals in the fields of law, political science, management, etc.

Scielo is a Brasilian digital library project that offers open access to over one thousand e-journals.

Wiki-journal for the identification, description and exchange of the scientific output of professionals and non-professionals. Accurate description of over 1,300 scholarly journals pertaining to all areas that may or may not be openly accessible and are available either in print or online.

Érudit is a university consortium comprising the Université de Montréal (UdeM), the Université Laval and the Université du Québec à Montréal (UQAM). It provides access to documents in the fields of social sciences, human sciences and natural sciences: scholarly journals, books, proceedings, theses and other documents and data. The website has a full-text search engine.
Most of the texts available on Érudit are openly accessible. The platform has a filtered access principle based on a 2-year moving wall: documents published in the course of the past two years are only available to subscribers. All earlier publications are openly accessible.
Érudit brings together around fifty Canadian and French publishers. The following journals (whole collection) are openly accessible: Cahiers québécois de démographie; Drogues, santé et société; Enfances, Familles, Générations; Psychiatrie et violence; Romanticism and Victorianism on the Net; Environnement urbain / Urban Environment.

A web platform for journals in the humanities and social sciences.
Persée is a web platform for journals in the humanities and social sciences that was created by the French government. It is intended is to provide online access to the retrospective collections of this vast field of study. The broad dissemination, based on public and open access, of this rich scientific heritage helps to promote French scientific research output.

A web platform for journals in the humanities and social sciences. It provides the Université de Nice Sophia Antipolis with an e-publishing tool similar to open institutional archives. The technological choices made for this platform mean that it is now a technical model for others.

Created in 1999, this portal provides access to the full text and Table of Contents of 378 (in July 2013) e-journals in the humanities and social sciences. The platform was developed by CLEO (Centre pour l'Edition Electronique Ouverte, French agency for the development of open access e-publishing). Most of the journals are supported directly or indirectly by the CNRS (Centre national de la recherche scientifique, French agency for scientific research), CNL (Centre national du Livre, French agency dedicated to the book industry), universities or other higher education institutions. They are published by learned societies, major research institutes, university presses or private publishers.

Directory of SHS-dedicated OA journals. Basic Dewey indexing. Journals can be sorted according to the language in which they are published. You can access the cited journals by clicking on the pictures. Over 6,900 journals have been indexed to date.
(our thanks go to Dominique Poggi, Toulouse 2, for suggesting this link)

BioMed Central is an independent publisher in the fields of biology and medicine. It provides open and free access to 257 validated journals (data of July 2013) that are published according to a special business model: the publication fees are borne by the authors or by the institutions to which they belong. Biomed Central was acquired by Springer in 2008.

Web platform providing full-text access to articles from journals dedicated to the biological sciences.

PLOS is an active player in OA, launched in 2001 by the National Library of Medicine. The aim was to put pressure on commercial publishers and force them to accept the free online publication of an article six months after it had been published in a journal. The launching did not have the desired effect, so PLOS began creating new OA journals. It now publishes seven hard science journals including PLOS Biology and PLOS Medicine.