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 cua » truong cua, trung tuan, trung cap
cua tong » cua cong, cua dong, cua nong
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: toan ((thiet tach) OR (thuat tach)) - thanh trung cua tong ((cong dan) or (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toan ((thiet tach) OR (thuat tach)) - thanh trung cua tong ((cong dan) OR (cong san)) toan cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toan ((thiet tach) OR (thuat tach)) - thanh trung cua tong ((cong dan) or (cong san)) toan cau*".