Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
trinh cua » trinh luat, trinh luan, trinh chat
dung cong » dung trong
hoi hieu » hoi phieu, hoi tieu, moi hieu
tinh cua » sinh cua, tinh chat, tranh cua
quan dau » quan cau, qua dau, quan dac
co hieu » cao hieu, doc hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((co hieu) or (hoi hieu)) lang - hanh ((tinh cua) or (trinh cua)) dung cong trinh quan dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co hieu) OR (hoi hieu)) lang - hanh ((tinh cua) OR (trinh cua)) dung cong trinh quan dau.
• Adding a wildcard symbol may retrieve word variants: ((co hieu) or (hoi hieu)) lang - hanh ((tinh cua) or (trinh cua)) dung cong trinh quan dau*.