Perhaps you should try some spelling variations:
hieu sach » chieu sach, hieu cach, dien sach
bang cong » dang cong, hang cong, dung cong
bang song » nang song
doc hieu » toc thieu, hoc thieu, hoc hien
anh dang » anh dong, anh dung, anh bang
dan toan » van toan, dan than, manh 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: doc hieu sach - ((canh tranh) or (anh dang)) chua ((bang cong) OR (bang song)) dan toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sach - ((canh tranh) OR (anh dang)) chua ((bang cong) OR (bang song)) dan toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sach - ((canh tranh) or (anh dang)) chua ((bang cong) OR (bang song)) dan toan ban".
• Adding a wildcard symbol may retrieve word variants: doc hieu sach - ((canh tranh) or (anh dang)) chua ((bang cong) OR (bang song)) dan toan ban*.