Here are 10 literature search tools that will make your scientific literature search faster and more convenient. All of the presented literature review software is free and follows Open Science principles.
Traditionally, scientific literature has been tucked away behind paywalls of academic publishers. Not only is the access to papers often restricted, but subscriptions are required to use many scientific search engines. This practice discriminates against universities and institutions who cannot afford the licenses, e.g. in low-income countries. Closed publishing also makes it hard for persons not affiliated with research institutes, such as freelance journalists or the public, to learn about scientific discoveries.
The proportion of research accessible publicly today at no cost varies between disciplines. While in the biomedical sciences and mathematics, the majority of research published between 2009 and 2015 was openly accessible, this held true only for around 15 percent of publications in chemistry. Luckily, the interest in open access publishing is steadily increasing and has gained momentum in the past decade or so.
Many governmental funding bodies around the world nowadays require science resulting from grant money they provided to be available publicly for free. The exact requirements vary and UNESCO is currently developing a framework that specifies standards for the whole area of Open Science.
Once I started my research on the topic, I was astonished by just how many free Open Science tools for literature review already exist! Read on below for 10 literature search tools — from a search engines for research papers, over literature review software that helps you quickly find open access versions of papers, to tools that help you save the correct citation in one click.
Tools for Literature review
First, an overview of the literature search tools in this blog post:
- ScienceOpen
- The Lens
- Citation Gecko
- Local Citation Network
- ResearchRabbit
- Open Access Button
- Unpaywall
- EndNote Click
- Read by QxMD
- CiteAs
I divided the tools into four categories:
- Search engines for research papers
- Literature review software based on citation networks
- Locating open access scientific papers, and
- Other tools that help in the literature review
Here, we go!
Search engines for research papers
The best place to start a scientific literature search is with a search engine for research papers. Here are two you might not have heard of!
ScienceOpen
Want to perform a literature search and don’t want to pay for Web of Science or Scopus or perhaps you are tired of the limited functionality of the free Google Scholar? ScienceOpen is many things, among others a search engine for research papers. Despite being owned by a private company, this scientific search engine is freely accessible with visually appealing and functional design. Search results are clearly labelled for type of publication, number of citations, altmetrics scores etc. and allow for filtering. You can also access citation metrics, i.e., display which publications have cited a certain paper.
The Lens
Recommended by a reader of the blog (thank you!), the Lens is a search tool that doesn’t only allow you to search the scholarly literature but patents too! Millions of patents from over 95 jurisdictions can be searched. The Lens is run by the non-profit social enterprise Cambia. The search engine is free to use for the public, though charges occur for commercial use and to get additional functionality.
Literature Review software based on citation networks
The next category of tools we will be looking at are a bit more advanced than a simple search engine for research papers. These literature search tools help you discover scientific literature you may have missed by visualising citation networks.
Citation Gecko
The literature search tool Citation Gecko is an open source web app that makes it easier to discover relevant scientific literature than your average keyword-based search engine for research papers. It works in the following way: First you upload about 5-6 “seed papers”. The program then extracts all references in and to these seed papers and creates a visual citation network. The nodes are displayed in different colours and sizes depending on whether the papers are citing a seed paper or are cited by it and how many, respectively. By combing through the citation network, you can discover new papers that may be relevant for your scientific literature search. You can also increase your citation network step by step by including more seed papers.
This literature review tool was developed by Barney Walker, and the underlying citation data is provided by Crossref and Open Citations.
Local Citation Network
Similar to Citation Gecko, Local Citation Network is an open source tool that works as a scientific search engine on steroids. Local Citation Network was developed by Physician Scientist Tim Wölfle. This literature review tool works best if you feed it with a larger library of seed papers than required for Citation Gecko. Therefore, Wölfle recommends using it at the end of your scientific literature search to identify papers you may have missed.
ResearchRabbit
As an alternative to the literature search tools Citation Gecko and Local Citation Network, a reader of the blog recommended ResearchRabbit. It’s free to use and looks like a versatile piece of literature review software helping you build your own citation network. ResearchRabbit lets you add labels to the entries in your citation network, download PDFs of papers and sign up for email alerts for new papers related to your research topic. Instead of a tool to use only once during your scientific literature search, ResearchRabbit seems to function more like a private scientific library storing (and connecting) all the papers in your field.
Run by (former) researchers and engineers, ResearchRabbit is partly financed through donations but their website does not state where the core funding of this literature review software originates from.
Locating open access scientific papers
You may face the problem in your scientific literature search that you don’t have access to every research paper you are interested in. I highly recommend installing at least one of the open access tools below so you can quickly locate freely accessible versions of the scientific literature if available anywhere.
Open Access Button
Works like the scientific search engine Sci-hub but is legal: You enter the DOI, link or citation of a paper and the literature review tool Open Access Button displays it if freely accessible anywhere. To find an open access version, Open Access Button searches thousands of repositories, for example, preprint servers, authors’ personal pages, open access journals and other aggregators such as the COnnecting REpositories service based at The Open University in the UK (CORE), the EU-funded OpenAire infrastructure, and the US community initiative Share.
If the article you are looking for isn’t freely available, Open Access Button asks the author to share it to a repository. You can enter your email address to be notified once it has become available.
Open Access Button is also available as browser plugin, which means that a button appears next to an article whenever a free version is available. This search engine for research papers is funded by non-profit foundations and is open source.
Unpaywall
Unpaywall is a search engine for research papers similar to Open Access Button — but only available as browser plugin. If the article you are looking at is behind a paywall but freely accessible somewhere else, a green button appears on the right side of the article. I installed it recently and regret not having done it sooner, it works really smoothly! I think the plugin is a great help in your scientific literature search.
Unpaywall is run by the non-profit organisation Our Research who has created a fleet of open science tools.
EndNote Click
Another browser extension that lets you access the scientific literature for free if available is EndNote Click (formerly Kopernio). EndNote Click claims to be faster than other search engines for research papers bypassing redirects and verification steps. I personally don’t find the Unpaywall or Open Access Button plugins inconvenient to use but I’d encourage you to try out all of these scientific search engines and see what works best for you.
One advantage of EndNote Click that a reader of the blog told me about is the side bar that appears when opening a paper through the plugin. It lets you, for example, save citations quickly, avoiding time-consuming searches on publishers’ websites.
As the reference manager, EndNote Click is part of the research analytics company Clarivate.
Other tools for literature review
This last category of literature search tools features a tool that creates a personalised feed of scientific literature for you and another that makes citing the scientific literature effortless.
Read by QxMD
Available as an app or in a browser window, the literature review tool Read lets you create a personalised feed that is updated daily with new papers on research topics or from journals of your choice. If there is an openly accessible version of an article, you can read it with one click. If your institution has journal subscriptions, you can also link them to your Read profile. Read has been created by the company QxMD and is free to use.
CiteAs
You discovered a promising paper in your scientific literature search and want to cite it? CiteAs is a convenient literature review tool to obtain the correct citation for any publication, preprint, software or dataset in one click. Funded by the Alfred P. Sloan Foundation, CiteAs is operated partly by the non-profit Our Research.
Beyond literature review tools
There you have it, 10 tools for literature review that are all completely free and follow Open Science principles.
Of course, finding a great literature review tool, such as a search engine for research papers or a citation tool, is only one essential part in the whole process of writing a scientific paper. If you would like to learn a complete process to write a scientific article step by step, then you’ll love our free training. Simply click on the orange button below to watch it now (or sign up to watch it later).
