Perhaps you should try some spelling variations:
thieu sach » chieu sach, hieu cach, theo sach
thien hach » thien thanh, hien hanh
thanh dong » thanh duong, thanh cong, hanh dong
tong cong » cong cong, dung cong, dang cong
dong cua » dung cua, cong cua, huong cua
san toan » van toan, dan toan, manh toan
toan tap » toan ban

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

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