Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trinh quan » tinh quang, trinh luat, trinh han
trinh cua » tinh cua, trinh luat, trinh luan
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan ban » van 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 quang - hanh ((trinh cua) OR (trinh quan)) trong cong dan toan ban~.
• Adding a wildcard symbol may retrieve word variants: doc hieu quang - hanh ((trinh cua) or (trinh quan)) trong cong dan toan ban*.