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This is the third, and last part in a three part series on finding free scientific papers. You can read the first part here: Part I: A day in the life of an English physician and the second part, where I compare different methods, here.

Today, I will show you how to use my new favorite method.

How to find free scientific publications

1. Go to the NCBI.

2. Choose the link to PubMed. (It’s in the top blue bar, under the DNA icon)

3. Click the Limits tab (circled below).


4. Click the box next to “Links to free full text.

5. Select any other Limits that might apply.

I often pick English for the language since I can’t read any other language. I wouldn’t try to impose too many limits at first, though, since you don’t always know how articles were categorized when they entered the database. You can always narrow the search later.

6. Enter your search terms and click “Go.”

7. Click the Review tab if you wish to read reviews, click links to the articles if you wish to see the abstract and get a link to the publication.

Here’s what the results look like:


I opened up the Sort By menu to show you how to sort by the publication date.  If you choose this option, the most recent articles appear at the top of the list.

We’ll tackle the Save your Search link at a later time, but this is a feature that I really like.

Where to find more info
For more information on choosing search criteria, Boolean logic, and using PubMed, we have two animated tutorials at Geospiza Education that cover using PubMed, and I have a chapter on Entrez in my new book (A Beginner’s Guide to Molecular Structures).

1. Cancer Biology covers the different types of literature databases, Boolean operators, combining queries, limiting searches, and using the search history.

2. Allelic Variants of Superoxide Dismutase demonstrates many ways to find information about genetic diseases, and includes my topic for today; how to find free papers in PubMed.

3.  Some of yesterday’s readers contributed their favorite search strategies in the comments section.  If you’re looking for specific papers, these are some great ideas.   

May you find what you’re searching for!


 [Uh, hey Doc?

Yes, Suzy and Johnny? 

When you did that experiment yesterday – you know – the one where you compared the number of papers that you found with different methods and showed that there were 219,985 papers from PubMed -with limits- and 171,702 papers from PubMed Central, well, were the papers that you found with PubMed Central, the same papers that you found with PubMed with limits?

Hmmm……..I don’t know.

It sounds like we need to do another experiment.]

Read the whole series:

  • part I A day in the life of an English physician,
  • part II Comparing different methods,
  • part III My new favorite method,
  • part IV One last experiment


Copyright Geospiza, Inc.


  1. #1 coturnix
    May 23, 2007

    Hopefully in a few years ALL scientific papers ever published will be available to everyone for free.

  2. #2 Margaret Henderson
    May 23, 2007

    I have just finished reviewing over 30 PubMed interfaces for a library guide and one is good for finding free full text:

    PubMed Gold (Ye Olde Free Full Text Miner http://www.neurotransmitter.net/ftsearch.html ) finds PDFs for PubMed citations by automatically searching Google. Be aware that incorrect links may sometimes appear for articles with short, common titles. Links to free full text articles indexed by PubMed are also displayed with some citations.

    It doesn’t really allow for a complex PubMed Search but it is something you might want to try.

  3. #3 Sephy
    May 23, 2007

    Thanks for the serial posts! Both interesting and informative.

    Regarding the physician you mentioned in the 1st post, I guess that poor guy might be lacking in some basic training…And as I see, most, if not all, university libraries provide off-campus accesses to databases and journals they subscribed to.

    As a graduate student in China, I find myself lucky in a university which generously keep widely covered subscriptions. Sometimes, however, I still run into exceptions. I commonly use this strategy to obtain the full-text I need:

    1. PubMed & PMC & HighWire: In most occasions, this combinatory inquiry would provide the full-text available, including purchased and free;

    2. Google Scholar & Google: Both used to search with the precise title of my target article(“”) along with two limits: inurl:pdf or intitle:pdf. Google is sometimes useful because many authors now self-deposit their publications and some journals even encourage them to.

    3. Social connections: If above routes don’t work, I might ask for help in BBS or professional forums in hopes of some nice guy would reply with the article for me. Recently I’ve got used to request a reprint directly from the author. Although social connections can’t provide immediately available full-text, I can expect further discussions with the author.

    Well, there’re also ‘grey’ or obviously illegal routes underground to access full-text of articles that would otherwise cost some $30 pay-per-view!…

    No wonder open-access journals such as BMC, PLoS and probably NEJM get very popular here.

  4. #4 basingstoke
    May 23, 2007

    Thanks for this. I teach at a university with rather spotty subscription coverage, which can make research rather frustrating. I will definitely refer my students to this helpful howto.

  5. #5 Steck
    May 23, 2007

    I came across this useful series c/o Peter Subers Open Access Blog.

    I have used PubMed for the last 3 years as my main source for scientific/medical literature. I was not aware of the limits tab or the “Links to free full text” button so thanks.

    I expect the content of PubMed Central and UK PubMed Central to grow. Equally, I expect the number of authors publishing in Open Access Journals to grow. Self archiving is really important. This cannot be stressed enough.

    When faced with an abstract only, I simply email the corresponding author.

    88% send the pdf
    2% send the pdf on the condition that I cannot disseminate
    10% do not reply

    I request around 30 – 40 Papers a month. Top-tip, it’s always useful to explain to an Author why you are interested in their work and then to thank them for sending it.

    As such, if you can’t get access to the Paper that you are looking for, simply email the corresponding Author and in by far the majority of cases, you’ll be sent the Paper/article.

    Only last night I was trying to locate a new Paper. The Journal would not even send the Authors a Postprint. $80 to access a copy. After pleading with the Journal directly, they still would not let me have a free copy but they did reduce the cost of accessing the Paper (to anyone) down to $8 !!

    In both cases, if ya don’t ask – ya don’t get !!!

  6. #6 alf
    May 24, 2007

    The ‘free’ button at the top of HubMed search results – http://www.hubmed.org – does essentially the same thing (setting the limits).

    There’s a bookmarklet here you can use to help with automatically requesting a PDF from the author: http://hublog.hubmed.org/archives/001385.html

  7. #7 David Bradley
    May 24, 2007

    I wrote a similar post last year about how to hack research journal websites and get research papers for free. I was not advocating anything illegal despite my use of the word “hack”, just a few tips and tricks on where to find those free papers.

    Hope you don’t mind my passing on the relevant link here, I think I found one or two extra routes you have not yet mentioned.


  8. #8 Sandra Porter
    May 25, 2007

    Thanks everyone for the wonderful suggestions!

  9. #9 CogSciLibrarian
    May 28, 2007

    This is a great series, but it breaks my librarian heart. 🙁
    A great resource to start with is … a great librarian. Hopefully you have one at whatever institution you’re affiliated with and they can tell you how to access their resources from off-campus. It can involve a quick trip to the library’s web site, a search through their journal locator, and then a login with your institutional id & password. It’s somewhat cumbersome, but it would have helped your English physician and possibly others.

    Also, if you’re affiliated with an institution, you can request that they get you articles you want by Interlibrary Loan — that means that your library will ask another library to send the article by pdf to them & they’ll get it to you. This will work at a college or corporate library — and your local public library will probably do it to. For free!! (that is, no cost to you).

    Beyond that, here are some additional tips:
    The Directory of Open Access Journals (DOAJ) is a great place to find free scientific articles online. Much of this is in PubMed I think, but probably not all. Here’s what they say about DOAJ: “This service covers free, full text, quality controlled scientific and scholarly journals. We aim to cover all subjects and languages. There are now 2701 journals in the directory. Currently 806 journals are searchable at article level. As of today 134219 articles are included in the DOAJ service.”
    You can search for articles or find journals by topic, title, or search.

    I agree with an earlier poster about the science search engine Scirus, at http://www.scirus.com. At their advanced search page, you can limit your search to discipline, scientific article, publication date, or web site. Unfortunately, you can’t limit to full-text articles, as you can in PubMed.

    Finally, you can tweak your Google searches to increase the chances of getting the full-text: As an earlier poster said, you can use quotes around the title of the article so you exclude results that have the words in the title of your article but *aren’t* that article: speech perception in infants vs. “speech perception in infants”, e.g. Another great trick in Google is to limit by filetype; since you know that many of the articles you want will be in pdf format, you can limit your results to those that are in pdf, with the command filetype:pdf. This will eliminate results which reference your article in a bibliography but don’t actually have the full-text.

    This search “speech perception in infants” filetype:pdf yields 1220 results, rather than the over 10,000 results from a search on the title alone.

    Sorry for the lengthy post, but my librarian heart just wants to be helpful.

  10. #10 Sandra Porter
    May 28, 2007

    Thanks CogSciLibrarian,

    That’s great information. I’m not at an institution any more except as adjunct faculty, but even so, many of your suggestions will still be quite helpful!

    I never knew about the pdf search before DOAJ. One of the best things about blogging is that I get to learn so much from the commenters!

  11. #11 CogSciLibrarian
    May 30, 2007

    I can’t resist adding these extra free resources:
    From India comes Open J-Gate, a great open access journal database, in which all articles are freely accessible. It appears to cover many disciplines, and they say that content goes back to 2001 and indexes almost 4,000 journals. See http://www.openj-gate.com/

    Stanford University’s Highwire Press offers several scholarly journals for free, often — but not always — after an embargo of 6-12 months. See http://highwire.stanford.edu/lists/freeart.dtl

    The American Museum of Natural History offers free access to all of its journals at http://library.amnh.org/ . This is 4 journals back to the beginning of the journal run, which is at least 1921.

    SciELO – Scientific Electronic Library Online — was “conceived to meet the scientific communication needs of developing countries, particularly Latin America and the Caribbean countries.” To that end, it offers free access to almost 300 journals, most of them without an embargo (i.e., up to the present issue) in many sciences & social sciences. See http://www.scielo.org/index.php?lang=en

    Finally (for the moment), if you like psychology as I do, check out the Psychonomic Society, which offers free access to its 7 journals, from 1991-2000. http://www.psychonomic.org/search/

  12. #12 Sandra Porter
    May 30, 2007

    Wow! These are wonderful, thank you CogSciLibrarian!

    Now, if only we can find more open access journals for teaching and education.

  13. #14 Antonieto tan
    June 23, 2007

    Assingnment 1: WIP1

    WIP1 codes for wound induced protein in corn Zea mays. WIP1 is homologous to Bowman-Birk proteinase inhibitor. It is a serpin-like protein. Serpin 1 of Arabidopsis thaliana is a suicide inhibitor for metacaspase 9.


    Eckelkamp C, Ehmann B, Schopfer P. 1993. Wound-induced systemic accumulation of a transcript coding for a Bowman-Birk trypsin inhibitor-related protein in maize (Zea mays L.) seedlings. FEBS Lett. 1993 May 24;323(1-2):73-6.

    Rohrmeier T, Lehle L. 1993. WIP1, a wound-inducible gene from maize with homology to Bowman-Birk proteinase inhibitors. Plant Mol Biol. 1993 Aug;22(5):783-92.

    Vercammen D, Belenghi B, van de Cotte B, Beunens T, Gavigan JA, De Rycke R, Brackenier A, Inz D, Harris JL, Van Breusegem F. 2006. Serpin1 of Arabidopsis thaliana is a suicide inhibitor for metacaspase 9. J Mol Biol. 2006 Dec 8;364(4):625-36.

  14. #15 wow gold
    December 30, 2008

    nice post

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