The purpose of these search is to search only figures with their captions in papers from the Open Access journals publisher, Biomed Central (BMC).
We do this with an html form that includes
in the Google search string. Any items the user enters in the search box above will be added to the search. The blank search, no additional strings returns about 150K figure pages, as of April 2006. It appears to return the normal resolution figures and their full captions, not the high-res. But that's not a problem, since after selecting a particular figure from what Google returns, you can lop off the last two items, in the URL, e.g., "figure/F2". The URL, so truncated, is the URL for the full paper containing the figure.
A note on wild card searches in Google: A few experiments showed that the number of asterisks used affects the search. The phrase "we used * to" returns 17K hits, whereas "we used * * to" returns 23K, including, apparently, more text in the * * position than the * position. Their wildcard search is pretty general - The following does what's expected: "we * to * the", 66K results. There are user discussion boards, blogs and web pages out there for various google search topics, so there is more wildcard wisdom and experience out there. A search on google search wildcards gets 360K hits.
Here is our BMC full text search page.