Perhaps you should try some spelling variations:
tinh dung » trinh dung, tin dung, tinh quang
hieu suat » hieu luat, hieu qua
mang hung » manh hung, dang hung, mang cung
tin mang » tin nang, ninh mang, tien manh
hung van » phung van, nhung van, dung van
van bien » van tien, van hien, vat bien
bien so » bien doi

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh dung (luan or quan) cao hieu suat ) or ( tin mang hung van bien so ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung (luan OR quan) cao hieu suat ) OR ( tin mang hung van bien so )).
• Adding a wildcard symbol may retrieve word variants: (( tinh dung (luan or quan) cao hieu suat ) or ( tin mang hung van bien so ))*.