oaDOI: New Search Engine for Open Access Research

A Digital Object Identifier (DOI) is a string of letters and numbers that was initially introduced in the year 2000 and is assigned to specific information to enable various search engines to find an article or report online. DOIs are assigned by a publisher and governed by the International DOI Foundation to ensure electronic availability of a published piece. They have a specific format beginning with “10” and identify specific organizations and publishers by unique codes according to their protocols. It is highly recommended that DOIs be included in both the printed and electronic copies of your research article.

Unfortunately, many websites that publish research work provide only the abstract and you must pay to access the full article. This can be frustrating not only for researchers who are searching for data and other information on specific subjects in their field but also to the general public who might be searching for specific scientific information or are just interested in learning more about the recent happenings in the world of science. The solution to this problem is called the “open access DOI” (oaDOI).

Getting Around the Paywall

oaDOI works like a DOI except that it provides access to an entire article when it’s available. For example, the following two links provide access to the same article; however, the first contains a paywall, while the second is free.

  • doi.org/10.1038/nature12373
  • oadoi.org/10.1038/nature12373


The oaDOI system is the brainchild of Heather Piwowar and Jason Priem, co-founders of Impactstory, and is funded by the Alfred P. Sloan foundation. The staff looks for open access copies of articles in print through search databases such as the Directory of Open Access Journals and BASE OA. They also search repository pages and journal articles to determine whether a free PDF exists.

Self-Archiving and Repositories

Several publishers encourage authors to take advantage of a repository at their educational institution and to self-archive (“green” open access) their papers there or in repositories that are focused on specific disciplines, such as arXiv. A repository at an educational institution is simply an online means by which to collect and preserve digital copies of materials from that institution, including research papers, data, and even course materials.

Authors can archive their papers before or after it is in print by following the protocols of the institution and as long as the publisher agrees. To check whether a publisher is onboard with this practice, a list is available on SHERPA/RoMEO. The list provides the names of nearly 1,000 publishers who have no restrictions but also includes those with an embargo period, those that require advance permission, and those that require a fee.

Easy to Use

In oaDOI, searching is as simple as pasting the DOI of interest on the homepage and letting the tool do the search for you. If an open access article is available, oaDOI will provide you with a link to the open access version of the paper using its library of repositories, directories, and databases. Another special use of oaDOI is that it can provide librarians with tools to help students find open access articles.

Although the oaDOI staff regularly checks institutional repositories for green open access listings, there are some limitations. Not all repositories are indexed in BASE, a major source of oaDOI’s list of free articles, and there can always be errors in the reporting process or the DOI string that lead to articles not being found; however, oaDOI encourages its users to report any errors using an online form and to provide other feedback to help the staff update the system.

Another downside is that registering a DOI involves a fee and not all smaller publishers want to incur that expense for hundreds or thousands of articles. If this is the case, these articles won’t be searchable with oaDOI. oaDOI also does not function well on mobile devices, but the problem has been identified and the staff is working to resolve it.

oaDOI vs Sci-Hub

Like oaDOI, Sci-Hub was the “first pirate website in the world to provide public access to tens of millions of research papers.” This online tool provides search capabilities for nearly 58 million academic papers in its library, and also like oaDOI, Sci-Hub can bypass paywalls. Sci-Hub was the brainchild of Alexandra Elbakyan, who saw the need to help researchers avoid the high cost imposed by publishers for accessing scientific papers behind paywalls. The program was not without controversy since it has been sued by publishers and has had to change its domain name several times because they have been blocked; however, it continues to be available.

oaDOI’s goal is to provide access to science for those who want to read about it. Although both Sci-Hub and oaDOI have the same mission, the creators of oaDOI believe that their tool is more powerful because it uses the already established DOIs to search various repositories and databases. As Sci-Hub continues to fight lawsuits by publishers and domain blockages, oaDOI’s creators believe that this program is “more sustainable over the long term.” oaDOI’s search process is more straightforward than Sci-Hub’s, and as more and more articles become open access, oaDOI will continue to grow and survive.

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