Perhaps you should try some spelling variations:
trai nghiep » trai nghiem, trac nghiem, mai nghiep
nghiep chan » nghiep thanh, nghiep luan, nghiep cua
dang thanh » dong thanh, dang hanh, hoang thanh
sanh trai » anh trac, hanh tai, sinh trac
nghi duoc » nghia duoc, nghi cuoc, nghiem duoc
nghe duoc » nghiem duoc, nghe nuoi, che duoc
chan hoi » chan hai, cham hoi, phan hoi
so sanh » do sanh
so dang » su dang, so dan, so dung

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( so sanh trai nghiep chan hoi ) or ( so dang thanh ((nghi duoc) OR (nghe duoc)) hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sanh trai nghiep chan hoi ) OR ( so dang thanh ((nghi duoc) OR (nghe duoc)) hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( so sanh trai nghiep chan hoi ) or ( so dang thanh ((nghi duoc) OR (nghe duoc)) hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( so sanh trai nghiep chan hoi ) or ( so dang thanh ((nghi duoc) OR (nghe duoc)) hoc ))*.