Perhaps you should try some spelling variations:
hieu sach » chieu sach, hieu cach, dien sach
thanh ban » thanh san, thanh van, thanh bac
doc hieu » toc thieu, hoc thieu, hoc hien
tuong va » truong va, thuong va, duong va
luong va » dung va
cong son » cong san, dong son, cong lon
cong so » cong san, cong hoa

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 - thanh ((tuong va) OR (luong va)) nhung ((cong son) or (cong so)) thanh ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sach - thanh ((tuong va) OR (luong va)) nhung ((cong son) OR (cong so)) thanh ban*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sach - thanh ((tuong va) OR (luong va)) nhung ((cong son) or (cong so)) thanh ban*".