Perhaps you should try some spelling variations:
thanh trung » thanh tung
thien hach » thien thanh, hien hanh
hien sach » dien sach, kien sach, chieu sach
vat dung » van dung, viet dung, mat duong
cong tan » cong tac, cong san, cong thanh
va dung » van dung, va duong, va ung
tan ran » tan tran, tan van, tan san
ran cau » van cau, ban cau, can cau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sach) OR (thien hach)) - thanh trung ((va dung) OR (vat dung)) cong tan ran cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien sach) OR (thien hach)) - thanh trung ((va dung) or (vat dung)) cong tan ran cau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sach) OR (thien hach)) - thanh trung ((va dung) or (vat dung)) cong tan ran cau*.