. . . . .

The nearest thing streaming video has to a search engine is Timecast at
http://www.timecast.com. Type in a very general topic such as “science” and
Timecast will offer a list of relevant sites from its 4000 streaming links. One
of its science links is to Cyberclinic at http://www.avglobal.com/cyberclinic, a
health site offering videos on a range of topics.