Perhaps you should try some spelling variations:
thanh trung » thanh tung
thiet tach » chiet tach, thien hach
thuat tach » thuat sach, thuat mach, thuat tac
trung hoac » trung hoc, trung hoa, trung ha
khong cong » khong cang, chong cong, khong con
thong cong » trong cong, tong cong, thong thong
thanh than » thanh thanh, thanh thang, thanh toan
than cau » toan cau, phan cau, than cap

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