Someone told me that there is a search engine that gets you most of research papers I may need for free.

He told me that this search engine is working based on using other members access to researches and make it available for all.

I tried searching for this search engine, but I could not find it.

Which search engine is it?

8 Answers 8


Your friend is probably thinking of Sci-Hub. Warning: it's likely illegal, including to use the service (as opposed to uploading stuff onto it), in most jurisdictions. If it's not already illegal in your jurisdiction, the trend is towards illegality (i.e. lawsuit after lawsuit has been ruled on, and they are usually in favor of the copyright holder).

If you want to do things legally, try something like Unpaywall, or ask your local librarian. Librarians are incredibly good at finding papers, and they can often access something for free even if you can't.

  • 3
    There has been a lot of debate about the legality of SciHub, both here and on other posts. Since continued debate is unlikely to lead to this answer changing, I have moved this discussion to chat. Please use the chat for continued legal debate.
    – cag51
    Commented Jun 14, 2020 at 17:52
  • See also this meta post.
    – cag51
    Commented Jun 14, 2020 at 17:54
  • I suggest editing this answer to be more focused on the topic of the question. Commented Jun 15, 2020 at 1:25
  • It is worth noting that using your library to access such work is free to you, but is often not free to the library.
    – commscho
    Commented Jul 4, 2020 at 16:32
  • 1
    @commscho that goes without saying - sort of like "turning the lights on is free to you, but must assuredly is not free for your university".
    – Allure
    Commented Jul 4, 2020 at 23:00

In addition to Sci-Hub and Unpaywall mentioned by Allure, there are also databases for scientific papers which were published legally with an Open Access license, such as CORE an BASE.


I would also add to the above the very commonly used resource Library Genesis, which is less for paywalled papers and more for pdf's of books, including textbooks, but do keep in mind that this definitely falls in the same legal gray area as Sci-Hub and things like torrenting copyrighted materials.

  • 3
    Good answer, but I'll add a remark: In many legal systems there is a clear distinction between torrenting and downloading copyrighted material. Bittorrent is a protocol that involves uploading parts of the file you are downloading to fellow downloaders. Hence if you use it you can be prosecuted not only for using copyrighted material yourself, but for making it available to others. The law typically punishes the latter more harshly. Commented Jun 13, 2020 at 11:04

Google has a search engine called Google Scholar. According to them, "It provides a simple way to broadly search for scholary literature. From one place, you can search across many disciplines and sources: articles, theses, books, abstracts and court opinions, from academic publishers, professional societies, online repositories, universities and other web sites."


Unpaywall is a good option to access free papers from most of the disciplines. Arxiv.org is an open-source community of free papers. It keeps on growing nowadays. https://doaj.org/ community-curated online directory that indexes and provides access to high quality, open access, peer-reviewed journals. Academia https://www.academia.edu/ offers a great way to connect to researchers. Refer to the paper you like and talk to the researcher and ask for it.


arXiv provides preprints of scientific articles that have not been peer reviewed. Many of the articles do subsequently get published in peer reviewed journals.



Simply put the full article name, and authors, as the input of the Google Search engine. Very often, the search engine will pull out some free version describing the same work by the same authors. It is most often some unfinished draft how it was while still in preparation and not yet reviewed, but you will be able to get the most of content, just less polished.


ResearchGate is also collecting the papers from authors and providing that to you for free.

Even thought publishers might serve the Research Gate with DMCA letters to take it down, it has a feature that allows authors to keep their papers "privately", which in that case, you can ask the author to let you see their papers, if it is "private".

The downside is that not all papers are in there. But, it has a good growing number of recent articles.

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