[Sigia-l] pre-written controlled vocabs?

[brendaj]

I know this products exists for purchase, but am having trouble finding it...

Currently looking for a pre-defined thesaurus to be used in indexing a 
database for search.  Looking for a 
place that sells thesauri based on topic, ex: "medical" or "education".

Can anyone point me to a company who sells such things?  I'd hate to spend 
hundreds of man hours 
reinventing the wheel if I don't have to.

-Brenda