Perhaps you should try some spelling variations:
cau sach » cao sach, hau sach, khau sach
rau sach » hau sach, khau sach, nam sach
anh dung » anh dong, anh huong, sach dung
cho dong » cho cong, co dong, pho dong
cong san » cong tac
song van » hoang van, trong van, duong van
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: cho ((cau sach) OR (rau sach)) - anh dung cho dong ((cong san) or (song van)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: cho ((cau sach) OR (rau sach)) - anh dung cho dong ((cong san) OR (song van)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "cho ((cau sach) OR (rau sach)) - anh dung cho dong ((cong san) or (song van)) toan cao".
• Adding a wildcard symbol may retrieve word variants: cho ((cau sach) OR (rau sach)) - anh dung cho dong ((cong san) or (song van)) toan cao*.