Must try search engines alternative to Google

We know that Google is the most dominant search engine in the world. This gives us most of the information in the web, even providing as back information from social media feeds like Facebook as you might already have been observed. Followed by Bing, AOL Search, Yandex, Duck Duck Go, Brave and more, try these less familiar search systems.  It provide excellent searchers in the world who specialize in books, science, other smart information as well.

Here are alternative search systems

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

If there are additional search system like above that you know but not listed above, please feel free to write in the comment.