The service works by searching for a queried paper’s unique digital tag — a string of numbers and letters known as its DOI, or digital object identifier — against those of articles gathered from 50,000 journals and repositories.
In June 2017, Unpaywall was integrated into a popular science search engine called Web of Science, which is operated by Clarivate Analytics.
Once Unpaywall’s integration is complete in November 2018, searches carried out on Scopus for free-to-read literature will also find articles on publisher platforms, even if the journal publishes a mix of open-access and paywalled articles.
This will boost the number of freely available articles in Scopus to 7 million, which is still around 13 million articles fewer than are listed in Unpaywall’s database as freely available (See 'Unpaywall Revolution').
On 26 July, Elsevier announced plans to integrate Unpaywall into its Scopus database searches, allowing it to deliver millions more free-to-read papers to users than it does currently.
Scopus’s embrace of Unpaywall, along with similar moves by other search engines, means that much more open-access content is now at researchers’ fingertips.Dimensions, a service run by Digital Science that launched this year, used Unpaywall from the get-go.These companies, and now Elsevier, pay a subscription fee for a feed of Unpaywall’s database that is updated weekly.These archives, which are operated by universities, funders and others, host a large portion of articles in Unpaywall’s database, but were difficult to search systematically in the past.Scientists using Scopus can filter their results to find freely available papers, but the database links to only around 1.5 million papers published in fully open-access journals.In the meantime, to ensure continued support, we are displaying the site without styles and Java Script.After being kicked out of a hotel conference room where they had participated in a three-day open-science workshop and hackathon, a group of computer scientists simply moved to an adjacent hallway.Impactstory also offers free access to the Unpaywall database (updated twice a year for non-subscribers), the browser plug-in and an interface that allows programmers to interact with Unpaywall to retrieve data.Since its launch, Unpaywall’s technology has also been integrated into many university-library discovery systems, so that users can easily find freely available versions of research papers in institutional repositories. You are using a browser version with limited support for CSS.To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer).