PubMed has implemented more changes to assist users in assessing the results of their searches. Last month, we highlighted the new filters in PubMed, which replaced the Limits feature. Late in June, the NCBI introduced new PubMed Discovery Tools: a "Results by year" graph and "PMC images search".
These new features display in the right side column (known as the "Discovery column") of PubMed search results.
The "Results by year" feature shows a bar graph of search results grouped by year. Mouse over any bar in the graph to see the number of search results from that year. Click on the bar to view only the results from that year.
The "PMC images search" retrieves images from papers in the PubMed Central database of free full text that appear in papers from your search results. A minimum of 4 relevant images are shown, with the option to "See more" under the thumbnail images. Mouse over a thumbnail to see a larger version of the image, complete with its caption and a link to the full text article in PubMed Central.
The "Results by year" and "PMC images search" tools will not appear in every PubMed search.
- "Results by year" requires at least 1,000 results to be retrieved from your PubMed search
"PMC images search" requires that
- at least 250 results are retrieved from your PubMed search
- searches must not include Boolean operators (i.e. "HSP70 brain" will retrieve PMC images, but "HSP70 AND brain" will not retrieve images)
- at least 4 images must be retrieved from PubMed Central, using a term-weighted algorithm
- special filters must not be in effect before your PubMed search (but if you use filters after your search, images will be retrieved)
For more information on the Discovery Tools in PubMed, see the National Library of Medicine Technical Bulletin feature on these tools.