Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, hieu cach
thanh tung » thanh cong
nhung cong » dung cong, thong cong, hang cong
hoc thieu » toc thieu, hoc hien
tam nhung » tham nhung, cam nhung, nam nhung
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than

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 thieu sach - ((thanh trung) OR (thanh tung)) tam nhung cong ((dan toan) OR (dan than)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sach - ((thanh trung) OR (thanh tung)) tam nhung cong ((dan toan) or (dan than)) cau~".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sach - ((thanh trung) OR (thanh tung)) tam nhung cong ((dan toan) or (dan than)) cau*.