The Best Free Tools for Finding Research Papers
A comparison of the free search engines and tools for finding research papers: Google Scholar, Unpaywall, CORE, BASE, Semantic Scholar, Europe PMC and DOAJ.
No single site has every research paper. The free tools below each do one job well, and knowing which to reach for saves a lot of time. They fall into two groups: tools that find a free copy of a paper you already know about, and search engines for discovering papers on a topic.
For finding a free copy of a specific paper
Research Papers Free
Our own finder takes a DOI, a link or a title and checks the open-access indexes for a legal free copy. It tells you which version each copy is, and every paper gets a page you can share. Nothing to install.
Unpaywall
Unpaywall maintains one of the main databases of free copies, and our finder relies on its data. It also offers a browser extension that shows a small tab on a publisher's page when a free copy exists. The extension suits people who browse journal sites all day.
Google Scholar
Scholar links to free PDFs it finds anywhere on the web, including authors' personal pages. Our guide explains how to find free PDFs on Google Scholar.
For discovering papers on a topic
Google Scholar
The broadest coverage of any free academic search engine, across every subject. Its weakness is filtering: you cannot limit a search to free papers only.
CORE
CORE gathers papers from thousands of university and subject repositories around the world, so almost everything it returns is free to read. It is a good choice when you only want results you can actually open.
BASE
BASE is run by Bielefeld University Library in Germany and indexes repository content worldwide. It lets you filter results to open-access items and is strong on theses and material in languages other than English.
Semantic Scholar
Built by the Allen Institute for AI, Semantic Scholar is strongest in computer science and biomedicine. It shows which later papers cite a result and highlights the most influential citations, which helps when you are tracing how an idea developed.
Europe PMC and PubMed
For medicine and the life sciences these are the specialist choices. Our guide to PubMed and PubMed Central explains how to limit a search to free full text.
DOAJ
The Directory of Open Access Journals lists journals in which every article is free. It is useful for checking whether a journal is a genuine open-access title, and you can search the articles in the journals it lists.
arXiv and other preprint servers
For physics, mathematics and computer science, searching arXiv directly finds the newest work, often months before it reaches a journal.
Which should you use?
- You have a specific paper in mind: use the finder, then Google Scholar.
- You want to explore a topic and read what you find: use CORE, or BASE with its open-access filter switched on.
- You want the widest possible search: use Google Scholar, then check each interesting result in the finder.
- You work in medicine or biology: start with PubMed or Europe PMC.
When a paper has no free copy anywhere, our guide to reading research papers for free covers what to do next.
Find a free copy of a paper
Paste a DOI, a link to the paper or its title, and we will look for a free, legal copy. No signup.
Frequently asked questions
What is the best free alternative to a university library?
For a specific paper, an open-access finder is the quickest check. For exploring a topic, CORE returns mostly free papers and BASE can filter its results to open access.
Is Google Scholar or CORE better?
Google Scholar covers more papers, including paywalled ones. CORE covers fewer, but almost everything it returns is free to read.
Do I need to install anything to find free papers?
No. Browser extensions are a convenience if you spend a lot of time on journal sites. A finder that takes a DOI, link or title does the same job on any device.