Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hanh trung » thanh trung, hanh trang, manh trung
tong cong » trong cong, cong cong, dang cong
dung cong » dung trong
cua tinh » cua sinh, va tinh, ha tinh
tac toan » tap toan, tam toan, hach toan
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sach) or (cua tinh)) - hanh trung tam ((tong cong) OR (dung cong)) tac toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (cua tinh)) - hanh trung tam ((tong cong) OR (dung cong)) tac toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (cua tinh)) - hanh trung tam ((tong cong) OR (dung cong)) tac toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (cua tinh)) - hanh trung tam ((tong cong) OR (dung cong)) tac toan ban*.