You can use google to search the archive on Yahoo! by taking advantage of some of google's advanced features: site and intitle.
In the google search box, you can type:
site:groups.yahoo.com intitle:CAD_CAM_EDM_DRO *keywords*
Replace *keywords* with what you want to search for. So, for example, to search for 'linux', you would type:
site:groups.yahoo.com intitle:CAD_CAM_EDM_DRO linux
The only catch to this is the this will only search the subject lines of the archive due to the way the Yahoo! allows google to index their pages.
There is an automated version of this search located at www.usd.edu/~jaskew/cnc/