No, you cannot export clips from DVD Player. Virtually all commercial DVDs are encrypted and the breaking of that encryption (such as for making copies) is a violation of the Digital Millennium Copyright Act of 1998. DMCA stomps on any "fair use" rights you thought you had, provided you live in the USA or any country that has close ties to the USA. That's why Apple's DVD Player provides no such feature.
That hasn't stopped others from breaking the system. For simplicity's sake, I would recommend downloading
MediaFork and using it to extract the specific chapters you wish to use.