Perhaps you should try some spelling variations:
thanh trung » thanh tung
thiet tach » chiet tach, thuat tach
thien hach » thien thanh, hien hanh
cua thuong » cua truong, cua phuong, ca thuong
cua thong » cua khong, cua tong, suat thong
cong dan » cong san, cong tan, huong dan
dan phan » doan phan, dan chan, van phan
phan cau » phan dau, phan cac, phan tu

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 ((cua thong) or (cua thuong)) cong dan phan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thiet tach) OR (thien hach)) - thanh trung ((cua thong) OR (cua thuong)) cong dan phan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thiet tach) OR (thien hach)) - thanh trung ((cua thong) or (cua thuong)) cong dan phan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thiet tach) OR (thien hach)) - thanh trung ((cua thong) or (cua thuong)) cong dan phan cau*.