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When you encounter a paywalled article, a colored tab gives you a link to a free PDF, if we can find one in our index of 10M+ open-access articles.

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When you view a paywalled scholarly article, Unpaywall automatically checks its open database of 16 million legal, open-access articles. If there's an open version somewhere, you'll see a green tab on the article. Click the tab and read for free, legally!

Unpaywall is a free, open-source project from Our Research, a nonprofit dedicated to making scholarly research more open, accessible, and reusable.

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