Open Access News

News from the open access movement

Friday, May 25, 2007

More on finding articles in PubMed and PubMed Central

Sandra Porter, Finding scientific papers for free, one more experiment, Discovering Biology in a Digital World, May 24, 2007.  Excerpt:

I meant for this to be a three part series, but in part II, I learned that one more experiment had to be done. I had to know if the articles I found in PubMed Central were the same articles that I found in PubMed.

Part I and part III cover the background and my favorite method. Now, we're going to find out if my favorite method is really enough....

To test this, I did a PubMed search with term "cancer," as before, and limited the search to free, full, text.

Then, I clicked the Preview/Index tab, opened the Filter field, and selected either the pubmed pmc free filter or the pubmed pmc filter....

Then, I clicked the AND button to add that term to my query. (Using the AND, OR, or NOT buttons works wonderfully, because everything is properly formatted with quotes and brackets.)

In part II, I found 220,219 articles on cancer in PubMed and 171,702 articles in PubMed Central. In today's experiment, I found that only 52,160 articles (a little more than a third, were shared between the two databases).

What's the take home message?

PubMed Central contains articles that are not available in PubMed (with limits). So, to get as many articles as you can, you do need to search both databases. And, if that doesn't work, my commenters (here and here) have left a number of excellent suggestions!