Teaching in universities in Vietnam

Hi,
I am interested in teaching English in universities in Vietnam.
There seems to be very few opportunities advertised for such opportunities , so I am wondering if anyone has any knowledge on the best websites to find such vacancies.
I also notice that many jobs in Vietnam are being advertised as part time hours only available, which would seem to therefore entail a lot of travelling around to get from job to job in order to ensure one gets enough teaching hours in a week to make a decent living. 
I would only be interested in full time positions teaching around 20 hours a week in areas from Danang and to the North of Danang.
Thanks to anyone who has any useful information regarding this enquiry.
Dai