Here are a selection of OA resources including search engines and online book and journal collections:

BASE is one of the world's largest search engines especially for academic web resources.  BASE provides more than 120 million documents from over 6,000 sources.  About 60% of the indexed documents are freely available.

Bioline International Open access to peer reviewed bioscience journals published in developing countries containing research in the areas of: public health, international development, tropical medicine, for and nutritional security, and biodiversity.

Biomed Central Online publisher of free peer-reviewed scientific articles in all areas of medical research and biology.

BioOne Open access biomedical science journals.

Cambridge Journals Digital Archives Free archival content to journals published by Cambridge University Press covering disciplines including: Science, Medicine, Humanities and Social Sciences, Language and Linguistics.

CORE aggregates the world's open access research and provides access to millions of articles.

DOAB Directory of Open Access Books provides access to over 12,500 academic peer-reviewed books and chapters

DOAJ Directory of Open Access Journals is a community-curated online directory that indexes and provides access to over high quality, open access, peer-reviewed journals.  DOAJ provides access to almost 12,000 journals and over 3 million articles.

Euro PubMed Central  is a repository, providing access to worldwide life sciences articles, books, patents, and NHS clinical guidelines.  It searches over 33 million abstracts and provides full-text to almost 5 million articles.

Google Books Find chapters and some complete books online, or search for suitable titles to buy of find in the Library.

Google Scholar  is an academic search engine that finds full-text articles, theses, eBooks as well as abstracts.  Google Scholar finds freely available OA content along with subscribed content available from the Library.  To see full-text available from the Library when off campus makes sure you go to Settings > Library Links > search 'Abertay' and select 'Abertay Library - View it @ Abertay'

Hathi Trust is a partnership of academic and research institutions, offering a collection of millions of book titles digitised from libraries around the world.

IAMCR Open Access Journals  International Association for Media and Communication Research is the preeminent worldwide professional organisation in the field of media and communication research.

IOP Journal Archive 1874-1998 Free archival content via JISC to all UK Higher and Further education institutions. IOP Journal Archive is a digital collection of nearly all the work published by the Institute of Physics between 1874-1998. The archive contains over 120,000 peer reviewed articles.

JSTOR Open Content  Explore multi-disciplinary academic content on JSTOR that is open to everyone. Search thousands of free journal articles and open access book chapters.

OAPEN  is a collection of freely accessible academic books, mainly in the area of Humanities and Social Sciences.

OpenDOAR  searches hundreds of Open Access repositories for freely available academic research articles.

Open Textbook Library  A growing catalogue of free, peer-reviewed, and openly-licensed textbooks.

PLOS  Public Library of Science.  PLOS is a non-profit organisation of scientists committed to making the world's scientific and medical literature freely accessible to scientists and to the public Health and life sciences journals.

PubMed Central  Free full-text archive of biomedical and life sciences journal literature at the U.S. National Institutes of Health's National Library of Medicine (NIH/NLM).

Sage Open  A peer-reviewed, open access journal that publishes original research and review articles on the social and behavioural sciences and the humanities. 

Springer Open 60+ peer-reviewed fully open access journals across all areas of sciences.

Wiley Open Access Journals Open access science journals from Wiley.