Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hieu sach » hieu cach, dien sach, hieu cac
chua bang » chu bang, chua nang, chua xang
bang cong » dang cong, bang song, hang cong
cong manh » cong danh, duong manh, cong thanh
manh toan » thanh toan, anh tuan, tinh toan
anh dang » anh dong, anh dung, anh bang
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: doc ((hieu sach) OR (chieu sach)) - ((canh tranh) or (anh dang)) chua bang cong manh toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sach) OR (chieu sach)) - ((canh tranh) OR (anh dang)) chua bang cong manh toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sach) OR (chieu sach)) - ((canh tranh) or (anh dang)) chua bang cong manh toan ban".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sach) OR (chieu sach)) - ((canh tranh) or (anh dang)) chua bang cong manh toan ban*.