Perhaps you should try some spelling variations:
thieu sach » thien hach, hieu cach, theo sach
chieu sach » chinh sach, chiet tach, chieu sang
duong cong » dung cong, luong cong, duong trong
tang cau » hang cau, bang cau, nang cau
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan ban » van ban
tang ca » tang cua, hang ca, tang ma

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)) - hanh ((tang cau) or (tang ca)) duong cong san toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (chieu sach)) - hanh ((tang cau) OR (tang ca)) duong cong san toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) OR (chieu sach)) - hanh ((tang cau) or (tang ca)) duong cong san toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) OR (chieu sach)) - hanh ((tang cau) or (tang ca)) duong cong san toan ban*.