Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
trung cong » truong cong, trong cong, trung uong
hieu quan » hieu qua, lieu quan, thien quan
doc hieu » toc thieu, hoc thieu, hoc hien
tinh cua » trinh cua, sinh cua, tinh chat
cong anh » cong danh, dong anh, hong anh
tuan ban » tuan bang, toan ban, luan ban

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 quan - hanh ((tinh cua) OR (trinh quan)) trung cong anh tuan ban~.
• Adding a wildcard symbol may retrieve word variants: doc hieu quan - hanh ((tinh cua) or (trinh quan)) trung cong anh tuan ban*.