In my experience Google Scholar already shows more counts than ISI Web of Science. A new paper in first monday highlights another search engine that allows even truncation of search terms*: Exalead is a European (Paris) based search engine which does allow truncation and has a nice interface too.
A new series of papers in the BMJ discusses some alarming consequences of “impact” measurements
The impact factor now has a worrying influence not just on publication of papers but on the science behind them too … One consequence has been to make universities prioritise laboratory based life sciences that produce research published in the highest impact factor journals, causing substantial damage to the clinical research base.
that goes beyond the previous view of Seglen.