Free Online Resources

You can use the Primo Knowledge Portal to search for e-books and other TU Berlin and UdK holdings as well as a number of journal articles. Use the default filter “All TU/UdK collections plus articles” to conduct your search.  The filter “Show only” in the results list allows you to quickly filter for electronic resources. Open access results are identified in the list and are freely available to everyone. Other resources may only be accessible to members of TU Berlin via a VPN or Shibboleth.

• Google Scholar is a search engine for academic literature which also indexes freely accessible articles.
•  BASE is one of the largest search engines worldwide for academic web resources, providing over 58 million open access documents.
• The Directory of Open Access Books (DOAB) is a catalog of peer-reviewed open access books. It also helps users to find trusted open access book publishers. As of November 2020, it contained over 33,424 books from 406 publishers.
• The Directory of Open Access Journals is the most important online directory of high quality, open access, and peer-reviewed journals. It currently contains over 15,500 journals and has indexed over 5 million articles (as of November 2020).
• The Karlsruhe Virtual Catalog (KVK) is a meta search engine for hundreds of millions of books and serials in library and book trade catalogs worldwide. It also includes libraries’ digital holdings. 
  Check the box Digital media only to only search for digital media. This link is particularly useful if you want to find freely accessible digital versions of older literature.
• Project MUSE offers access to articles and e-books from over 80 publishers. Search menu for freely accessible content. Some resources have been temporarily made freely accessible during the COVID-19 pandemic.
• The platform open-access.net offers general information about the topic of open access as well as an overview of subject-specific information and search options for freely accessible electronic resources.

Repositories are document servers hosted by universities or research institutes where academic materials are stored and made freely accessible. There are two types of repositories: institutional and subject-based.

• DepositOnce is TU Berlin’s own institutional repository and contains academic publications and research data from members of the University. These are openly accessible to anyone. The metadata from the nearly 10,000 publications can also be freely searched.
• You can find an overview of specialist or multidisciplinary repositories at Open Directory of Open Access Repositories (OpenDOAR) and in the registry of Open Access Repositories (ROAR)
• We have also compiled select subject-based repositories and preprint servers on our information pages for authors.

Browser extensions enable you to quickly and easily find freely accessible versions of papers or other scientific publications. We recommend installing the following extensions:

• Unpaywall automatically takes you to freely accessible versions. It is open source and does not collect extensive user data
• CORE aggregates over 200 million open access publications. The browser plugin takes you directly to the freely accessible version.
• Open Access Helper is available as an app for different devices. It uses Unpaywall and CORE to help you more easily find open access versions of academic articles behind a paywall.
• Open Access Button helps you avoid paywalls and delivers open access versions of academic publications.

If the publication you are looking for has a DOI, copy the links https://www.oadoi.org/ or http://doai.io/ into your browser and at the end of the URL, add the DOI of the publication you are searching for. This will take you directly to one of the free available versions – either the library has a license or the author has a secondary publication (example).

Many academics use the hashtag #ICanHazPDF to ask the Twitter community for help when searching for an article or directly email their colleagues.

We have put together a list of portals with Open Educational Resources (OER) for teaching and studying on the page Digital Teaching and Learning Materials 

• Cambridge Core Collection:  Articles on the coronavirus 
• Elsevier:  Novel Coronavirus Information Center 
• Emerald: Articles on the coronavirus 
• Jove: Coronavirus Free Access Resource Center (videos)
• Ovid: Ovid's COVID-19 Toolkit for Clinicians
• Oxford University Press: Articles on the coronavirus 
• Wolters Kluwer: Wolters Kluwer COVID-19 (Coronavirus) Resources
• COVID-19 publications: Collection from the Zentralbibliothek für Medizin