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Browser Extensions


Locating open access resources 

Sarah Dar, Scholarly Communications Officer 

Locating resources for your research can be time-consuming, and it can be difficult to know whether or not journal articles that you want to read can be freely accessed. Fortunately, there are a number of browser extensions which easily provide links to content that can be freely accessed either because the University has a subscription to the content or because the material is available open access. Outlined below are a couple that you may find helpful. They are quick and simple to install and could save you a considerable amount of time and effort when trying to locate material. 


Libkey Nomad 

LibKey Nomad is a browser extension that automatically provides links to full-text content of articles. As you come across literature via a web search, Nomad will help you to quickly and easily access any content the library has a subscription to in addition to any content that is available open access.  

Libkey Nomad works with a range of browsers including Chrome, Firefox, Microsoft Edge, Brave and Vivaldi. As well as identifying material that can be accessed on publisher websites, Nomad links to content that can be accessed in open access repositories, and it will also identify accessible content on PubMed and Wikipedia.  

Information on how to install Libkey Nomad can be found here:  


Once you have installed the extension, whenever you are on a webpage where an article is accessible you will see a Libkey Nomad banner alert on the lower left of the screen. By simply clicking ‘download pdf’ you will be able to download the article.  

download pdf button

If the university doesn’t have a subscription that provides access to an article but an open access alternative is available (e.g. an accepted manuscript in an institutional repository) Libkey Nomad will either link to the open access version or will enable you to download the pdf of the manuscript with one click. 

download manuscript button

 Libkey Nomad is a great tool for locating resources, particularly PDFs. It enables you to start your search for articles anywhere, not just on the library web pages. As library holdings data is so well integrated in Libkey Nomad, it works quickly and provides reliable access to resources.  

 If you have any questions about Libkey Nomad or require assistance please contact the Library via ASSIST 



Unpaywall is a browser extension that allows users to access open access articles as they search the web. It was developed by Impactstory a non-profit group who are “dedicated to making scholarly research more open, accessible, and reusable”. Unpaywall works with both Chrome and Firefox and provides one-click access to material, which makes it a more convenient tool than others such as OpenDOAR, Google and Google Scholar.  

Like Libkey Nomad, the Unpaywall plug-in identifies when full-text articles are available by displaying an icon- a green padlock symbol which, when clicked, will take you to open access content.  

Unpaywall locks

A grey padlock will be displayed where access is not available.  


Libkey Nomad uses Unpaywall data to provide access to open access versions of articles when access is not provided by the library’s subscriptions. If you are using Libkey Nomad you won’t need to install the Unpaywall plug-in as Nomad will direct you to the same open access content as Unpaywall. If you’re not using Nomad and would like a plug-in that will enable you to locate only open access contentnot content available on the university library’s subscription, then you should find Unpaywall very helpful 

A really useful feature of the Unpaywall plug-in is that it is possible to see whether the version of an article is Green, Gold or Bronze open access. When you install the plug-in (alternatively you can edit your settings later) you can select what they’ve termed ‘Nerd Mode’. Once you have enabled this, whenever you come across an article the colour of the padlock will change, depending on which type of open access it is.  

Unpaywall's colour code feature

Gold: Gold OA articles available from a fully Open Access journal. 

Green: Green OA articles on an institutional repository or preprint server. 

Bronze:  free to read on the current page, but published in a hybrid journal where a fee must be paid for access.  

One positive aspect of using Unpaywall is that it provides access to content that is genuinely legally open- many researchers upload articles to websites like and ResearchGate, but the sharing of this content may not be legal.  

To start searching for open access articles, download and install the Unpaywall browser extension, go to the Unpaywall website:  


New functionality in Library Search 

Although not a browser extension, this new function in Library Search will help you find journal articles quickly and easily. The new search box will enable you to search all content provided by the library as well as over 26 million open access titles, and provides fast, one-click direct access to the full text PDF and HTML articles. 

A search box has been added which enables you to search for a journal article using either the DOI or PubMed ID.  

LibrarySearch - find journal button

A DOI, or Digital Object Identifier, is a string of numbers, letters and symbols used to permanently identify an article or document and link to it on the web. DOIs always begin with the numbers 10.  

A PMID, also known as the PubMed reference number, is a number assigned by the NIH National Library of Medicine to papers indexed in PubMed. PubMed Central is an archive of full-text journal articles.  

You can find the DOI on the journal publisher’s website. The PMID can be found on the record on the PubMed website.  

Once you’ve added the DOI or PMID to the search box and clicked ‘find article’ you will be presented with several options: 


LibrarySearch download pdf button

You can download the PDF 

 LibrarySearch article link button

Follow the link to the article to access it 

 LibrarySearch access options button

Request the article via interlibrary loan 

 LibrarySearch view articles in context button

See the other articles in the same issue of the journal, and browse other issues/volumes.  


If you have any questions about this functionality or require assistance please contact the Library via ASSIST. 


Other browser extensions that you may find useful in helping you to access open access content include: 

CORE Discovery 

CORE Discovery locates open access copies of articles, using the CORE dataset of millions of full text OA papers, as well as the data of other providers. CORE Discovery claims to be able to locate scientific content without or with unknown DOIs. 

Open Access Button 

Open Access Button searches thousands of sources to connect you to an article instantly if it is freely available. It provides a service for requesting an article from the author if you don't have access via library subscription and the article is not yet open access.   


For more information please contact the Corporate Communications Team.

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