Perhaps you should try some spelling variations:
thiet tach » chiet tach, thuat tach
thien hach » thien thanh, hien hanh
nhung cong » dung cong, thong cong, hang cong
trung vap » trung cap, trung va, trung lap
trung van » truong van, trong van, trung va
cong san » cong tac
san hanh » san thanh, ban hanh, van hanh
hanh cap » hanh cac, hanh cat, hanh cad

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thiet tach) or (thien hach)) - thanh ((trung vap) OR (trung van)) nhung cong san hanh cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thiet tach) OR (thien hach)) - thanh ((trung vap) OR (trung van)) nhung cong san hanh cap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thiet tach) or (thien hach)) - thanh ((trung vap) OR (trung van)) nhung cong san hanh cap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thiet tach) or (thien hach)) - thanh ((trung vap) OR (trung van)) nhung cong san hanh cap*.