www.refseek.com - Academic Resource Search. More than a billion sources: encyclopedia, monographies, magazines.
www.worldcat.org - a search for the contents of 20 thousand worldwide libraries. Find out where lies the nearest rare book you need.
https://link.springer.com - access to more than 10 million scientific documents: books, articles, research protocols.
www.bioline.org.br is a library of scientific bioscience journals published in developing countries.
http://repec.org - volunteers from 102 countries have collected almost 4 million publications on economics and related science.
www.science.gov is an American state search engine on 2200+ scientific sites. More than 200 million articles are indexed.
www.base-search.net is one of the most powerful researches on academic studies texts. More than 100 million scientific documents, 70% of them are free
https://www.ecosia.org/
Ecosia is a not-for-profit tech company that plants and protects trees. By dedicating 100% of its profits to the planet, Ecosia has planted over 214,229,374 million trees since its founding in December 2009
Yandex is a technology company that builds intelligent products and services powered by machine learning. Our goal is to help consumers and businesses better navigate the online and offline world. Since 1997, we have delivered world-class, locally relevant search and information services.
Project Gutenberg is a library of over 75,000 free eBooks
“Protection. Privacy. Peace of mind. Get our browser on all your devices.
Search and browse with the DuckDuckGo browser for more protection. Unlike Chrome and other browsers, we don’t track you.”
Presearch.io
Presearch is a community-powered, decentralized search engine that provides better results while protecting your privacy and rewarding you when you search.
Reliable information for all kinds of research
Startpage is a global privacy technology company built around the principle of always putting privacy first. Our suite of easy-to-use privacy products helps anyone around the world to protect their personal data online.