General internet search engine showing only non-commerical sites?

Question

Are there any general internet search engines that can limit hits to exclusively free non-commercial websites? (No '.com's or '.biz's, no paywalls, no membership-based revenue models, etc.)

So, for example, a search for "foobar" would show results from Wikipedia, Project Gutenburg, and '.gov' sites, but not from Twitter, Facebook, Amazon, etc. The results of a search should not include SEO garbage.

Answer 1

1. Briefly about Kristinita'S Search

I have long been worried about the problem, which raised in @agc question. Recently I begin to develop Kristinita's Search — search engine, which searches for information only in open access sources, written by professionals in the theme.

I do not find choice except to add each website, which will be searched, manually. In my search engine not paywalls, internet-magazines, social networks, SEO garbage and so on. I add only sites, useful for science.

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2. Limits

1. I'm sorry, the project not ready yet. Please, do not hit me hard.
2. Kristinita's search only for Runet. I understand, that more be better to create search engine that include English and more languages, but I can not to do a huge amount of work.

About others limits and shortcomings see in this section.

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3. Examples

1. The construction term:

• Google: 7 sites to sell products, 1 forum thread, images and 1 science article.

• Kristinita's Search: 10 science articles.

Kristinita's Search not include commercial, non-science sites.

2. The chemical term

• CyberLeninka — 2 articles about BeO (only about toxical properties) and 9 casual mentions in the text.

• Kristinita's Search — 9 chemical articles about BeO, 1 casual mention.

Kristinita's Search was included more materials and have more relevance search result than CyberLeninka, Google Scholar, Google Academy, eLIBRARY and others science search engine in Russian language.

3. Aquarium fish

• Yandex: 9 amateur sites, images and Wikipedia.

• Kristinita's Search: 10 articles in professional journals for the aquarists.

Kristinita's Search included only materials written by professionals, not amateurs.

4. President of Russian Federation

• Yandex: Official site, Wikipedia, 2 news feed, 3 profiles in social networks, 2 sites of non-professional authors, 2 mass media sites

• Kristinita's Search: 6 biographies in mass-media, 3 biographies in wiki-sites, 1 biography of person bearing the same surname.

Kristinita's Search is encyclopedia and not included news and social networks.

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4. Additional links

Materials from links in Russian language.

• Detailed description of Kristinita's Search;
• More examples;
• About sites inclusion criteria in Kristinita's Search.

If you want to make similar search system, you may write me according to any of the contacts — I try to help you. Also, I will not refuse, if someone offer me any help.

Thanks.

Answer 2

Searx's Science only search will search 10 or so engines dedicated only to science! This will leave out Wikipedia though. It is a metasearch engine. Find instances here. https://asciimoo.github.io/searx/user/public_instances.html https://stats.searx.xyz/