The Open Access Button will shut down on November 18th, The OA.Works team recommend trying Unpaywall.
Click on the relevant icon below to install the extension to your browser.
When you discover the record of a paper on the web, you can click on the Open Access Button to locate a complete and free version of it that is immediately accessible:

Alternatively, you may search for an article's title, DOI or URL directly via the Open Access Button webpage:
For example,
Searching ...
Challenges and virtues of theory-driven education - a meta-study of variation theory implemented in early childhood mathematics education
will result in ...
This article is freely available!
https://www.tandfonline.com/doi/pdf/10.3402/edui.v7.28773?needAccess=true
If the Open Access Button cannot locate any immediately accessible version of the paper, it will attempt to email the relevant author/s for the purpose of acquiring the item.

