So that you can try this study for yourself, this Excel sheet gives the titles and the DOI (document index) of the most recent 500 articles in my database (prior to Nov. 12, 2012), taken from the Web of Science. Review the titles and flag those that seem likely to reject human-caused global warming. Then use the DOI to read the abstracts of the flagged articles. If global warming denial has a leg to stand on, at least a few articles out of 500 should clearly state that human-caused global warming is wrong and provide the evidence to back it up. See how many you find.
To use the DOI, copy it, then go to http://dx.doi.org. Enter the DOI you copied and hit go. If you wish to use the Web of Science accession number, you must have library access.