Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
hieu sach » chieu sach, hieu cach, dien sach
trinh cua » tinh cua, trinh luat, trinh luan
doc hieu » toc thieu, hoc thieu, hoc hien
tuan cao » toan cao, juan cao, quang cao
hong ha » dong ha, long ha
cong ha » cong hoa, dong ha, cong tac

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sach - hanh ((trinh cua) OR (trinh quan)) nhung ((hong ha) OR (cong ha)) tuan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sach - hanh ((trinh cua) or (trinh quan)) nhung ((hong ha) OR (cong ha)) tuan cao~".
• Adding a wildcard symbol may retrieve word variants: doc hieu sach - hanh ((trinh cua) or (trinh quan)) nhung ((hong ha) OR (cong ha)) tuan cao*.