Perhaps you should try some spelling variations:
thien thanh » tien thanh, thi thanh, hien hanh
thanh trung » thanh tung
thien hach » hien hanh
nhung cong » dung cong, thong cong, hang cong
trung van » truong van, trong van, trung va
van nhung » van nhuong, va nhung, van hung
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than

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

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