: A highly popular site that provides access to over 64.5 million academic papers by bypassing publisher paywalls through educational institution proxies.

: Similar to Unpaywall, it helps users find legal, free versions of research articles that are behind paywalls. Specialized Academic Search Engines

For discovering these papers, the following search engines are highly effective: Google Scholar Semantic Scholar CORE Baidu Scholar The best academic search engines [Update 2025] - Paperpile

: A legal tool that harvests open-access content from over 50,000 publishers and repositories, providing access to roughly 20 to 55 million scholarly articles.

: A Chrome extension that finds the DOI of a paper on your current page and automatically searches for it across various open-access repositories like ArXiV and the Internet Archive .

: A completely legal resource that indexes high-quality, peer-reviewed, open-access journals across all areas of science and technology.

To download research papers and academic articles for free as of late 2022 and early 2023, several specialized websites and tools are recommended:

: These platforms collectively offer over 10 million books and 85 million articles.