Perhaps you should try some spelling variations:
hieu sach » chieu sach, hieu cach, dien sach
hanh tong » hanh trong, han tong, hanh dong
tong luan » tang luan, dung luan, hang luan
hang cong » dang cong, hang nong, bang cong
vang toan » van toan, dang toan, quang toan
doc hieu » toc thieu, hoc thieu, hoc hien
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: doc hieu sach - hanh tong luan ((hang cong) or (trong cong)) vang toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sach - hanh tong luan ((hang cong) OR (trong cong)) vang toan cao.
• Adding a wildcard symbol may retrieve word variants: doc hieu sach - hanh tong luan ((hang cong) or (trong cong)) vang toan cao*.