Perhaps you should try some spelling variations:
thieu sach » thien hach, hieu cach, theo sach
chieu sach » chinh sach, chiet tach, chieu sang
canh manh » lanh manh, canh tranh, cach mang
dung cong » dung trong
van toan » van tuan, van tan, van thanh
dan than » dan chan, ban than, van than
manh va » hanh va, anh va, minh va
va dung » van dung, va duong, vat dung

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 (chieu sach)) - canh manh va dung cong ((van toan) or (dan than)) tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (chieu sach)) - canh manh va dung cong ((van toan) OR (dan than)) tap.
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) or (chieu sach)) - canh manh va dung cong ((van toan) or (dan than)) tap*.