{"id":2545,"date":"2017-05-26T13:14:41","date_gmt":"2017-05-26T16:14:41","guid":{"rendered":"http:\/\/blog.scielo.org\/en\/?p=2545"},"modified":"2017-05-26T13:17:46","modified_gmt":"2017-05-26T16:17:46","slug":"how-to-find-articles-in-open-access-tips-from-my-favorite-nerd","status":"publish","type":"post","link":"https:\/\/blog.scielo.org\/en\/2017\/05\/26\/how-to-find-articles-in-open-access-tips-from-my-favorite-nerd\/","title":{"rendered":"How to find articles in open access \u2013 tips from my favorite nerd"},"content":{"rendered":"

By Ernesto Spinak<\/strong><\/p>\n

\"Image:<\/a>

Image: Freepik<\/a>.<\/p><\/div>\n

Publication of academic research results in open access is becoming more frequent and it is estimated that millions of documents are currently available online. For this reason, it is important to have efficient tools to find the free versions of the articles that we need (without paying for subscriptions or buying individual articles and using legal methods). As the need creates the offer, in the last two or three years, free applications have emerged to meet the requirements of academics, librarians, researchers, and students in general. What does the market offers nowadays?<\/p>\n

This is where my favorite nerd, Aaron Tay – a librarian at the Singapore Management Library comes in, who recently wrote some notes1,2<\/sup> on his blog, analyzing various plugins for browsers and the aggregator services that allow finding almost instantaneously complete texts in open access.<\/p>\n

The following table shows the different services analyzed by Aaron Tay in several posts (the links are listed at the end of the post) with some comments and ratings of mine (which I consider myself a bit old to be a nerd!) Below in this post we will show examples of the two plugins that seem to us the most efficient ones – that is: they are the ones I use – but it should be a good exercise to do the tests yourself.<\/p>\n\n\n\n\n\n\n\n\n\n\n
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    \n 1. BASE<\/a>\n <\/ol>\n<\/td>\n
\n

This service created by the Bielefeld University Library in Germany is probably one of the largest and most advanced aggregators in the world, surpassing in November 2016 the 100 million documents. BASE ensures that at least 40% of the texts identified are in open access, and cannot be guaranteed to the rest because of lack of metadata in the repositories. Through the oadoi.org service, you have access to over 5,000 repositories. However, BASE does not index the contents of these full texts. The search interface is quite advanced, possibly the friendliest of the whole family of plugins reviewed in this post.<\/p>\n<\/td>\n<\/tr>\n

\n
    \n 2. CORE<\/a>\n <\/ol>\n<\/td>\n
\n

CORE claims to have about 70 million documents that, such as BASE, are retrieved through the OAI-PMH protocol. For this reason, they also have the same problem of linking the complete texts with certainty due to the lack of normalization of the metadata in the institutional repositories, in particular the "Green OA" (see note at the end of the table). On the other hand, CORE indexes the content of these complete texts.<\/p>\n<\/td>\n<\/tr>\n

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    \n 3. Dissemin<\/a>\n <\/ol>\n<\/td>\n
\n

It is available in beta version, indexes about 100 million documents. It is a simple version, for the time being limited to searching only by the author’s name. Delivers results quickly indicating which of them are available in open access.<\/p>\n<\/td>\n<\/tr>\n

\n
    \n 4. Lazy Scholar button<\/a>\n <\/ol>\n<\/td>\n
\n

Launched in 2014, it is a plugin that, so far, only works on Google Chrome. It is the most complex extension (something complicated too) and, among several services, it can check whether your institution has subscription services to the full text, present several citation metrics, get comments from systems like PubMed Commons, offers functions that allow you to create citations, and retrieve documents related to your query that may be of interest, also in open access.
\n A tip: When I installed it, for simplicity, I marked NO on almost all parameters. It’s worth analyzing them (even if you won’t use it later).<\/p>\n<\/td>\n<\/tr>\n

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    \n 5. OAIster<\/a>\n <\/ol>\n<\/td>\n
\n

Owned by OCLC, it is a collective catalog that claims to have more than 50 million records of open access resources from OAI-PMH collection of more than 2,000 sources contributing to the catalog. Records are also available in the WorldCat interface. It has the same limitations as those indicated for BASE, CORE and collections based on the OAI-PMH protocol, limitations that are explained at the end of this table.<\/p>\n<\/td>\n<\/tr>\n

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    \n 6. Open Access button<\/a>\n <\/ol>\n<\/td>\n
\n

It is a plugin created in 2013 by two students and must be installed in a browser that it is not Internet Explorer, but it is easily installed in Google Chrome. It has a few thousand registered users. In my experiments, however, I did not have much success.<\/p>\n<\/td>\n<\/tr>\n

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    \n 7. Google Scholar button<\/a>\n <\/ol>\n<\/td>\n
\n

Created in 2015, it is directly installed and is possibly the preferred option. See a separate example below in this post.<\/p>\n<\/td>\n<\/tr>\n

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    \n 8. Unpaywall button<\/a>\n <\/ol>\n<\/td>\n
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It is the newest member of the family, and may be a second choice. See a separate example below in this post.<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

Note on the limitations of \u201cOAI-PMH harvester\u201d<\/em><\/p>\n

The Open Archives Initiative Protocol for Metadata Harvesting<\/em> (OAI-PMH) is a protocol developed to collect metadata descriptions of electronic records deposited in files so that the service can create query indexes. The implementation of OAI-PMH requires metadata to follow the Dublin Core standard. Indexing engines and service aggregators based on the OAI-PMH protocol have difficulties with coverage of institutional repositories due to the fact that these repositories are very heterogeneous and use a large diversity of file management systems. Moreover, because it lacks clear metadata standards, it is not simple for indexing robots to determine whether or not the records distinguish the free full texts. This problem adds to the difficulties of indexing records based on Dublin Core metadata, as I described earlier in this blog3<\/sup> about indexing repositories by Google Scholar.<\/p>\n

Complementing the comments of the mentioned article1<\/sup>, to understand better, we must say that in the history of open access repositories, the OAI-PMH protocol was established to recompile only the metadata and in the complete texts. The reason behind this protocol was that it was assumed that most (if not all) of the repositories would offer the open access texts (such as the ArXiv model), and for this reason, in the OAI-PMH protocol there is currently no field to indicate whether the full text is open access or not.<\/p>\n

The problem then arises when indexing the thousands of institutional repositories due to the fact that the role they play for these institutions goes beyond simply filing full documents in open access. Among other purposes is to support scholars\u2019 “self-archiving”, to preserve a record of university activities, and to demonstrate the relevance of their scientific, economic, and social activities to increase their visibility and status. For these reasons, as Aaron Tay says, institutional repositories may contain no more than one-third of their full-text documents accessible. Because of these limitations, open access document aggregators ignore these problems, and index the repositories in their entirety, giving the mistaken idea that everything is available in free access to the full text.<\/p>\n

To run the tests, I installed the applications on my Google Chrome version, and the buttons appeared on the browser toolbar as shown in the figure below:<\/p>\n

(1) Lazy Scholar; (2) Google Scholar button; (3) Open Access button; (4) Unpaywall button;<\/p>\n

\"\"<\/a><\/p>\n

Google Scholar button<\/h3>\n

It is a plugin released in 2015 that can be installed simply and directly. How does it work? Let’s say you’re on a page that you did not access through Google Scholar, and you want to know if there’s a free-access version of this document. What you should do, then, is to mark the title of the article with the mouse and click on the icon in the toolbar (Number 2 in the Toolbar figure above). Google Scholar will search in the background and open in a secondary window on the right displaying all the free access versions that are indexed:<\/p>\n

\"\"<\/a><\/p>\n

Unpaywall<\/span> button<\/span><\/h3>\n

Once the extension is installed, when it reaches a page of any document, the icon of a padlock, which may be in different colors, will appear in the right margin of your screen, which has the following meanings:<\/p>\n