Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu qua, diep quang
nhung cong » dung cong, thong cong, hang cong
hieu quan » hieu qua, lieu quan, thien quan
trinh cua » tinh cua, trinh quan, trinh luan
cong tan » cong tac, cong san, cong thanh
tan phan » toan phan, than phan, van phan
phan cau » phan dau, phan cac, phan tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: nho ((hieu quang) OR (hieu quan)) - hanh ((trinh cua) or (trinh luat)) nhung cong tan phan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nho ((hieu quang) OR (hieu quan)) - hanh ((trinh cua) OR (trinh luat)) nhung cong tan phan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "nho ((hieu quang) OR (hieu quan)) - hanh ((trinh cua) or (trinh luat)) nhung cong tan phan cau".
• Adding a wildcard symbol may retrieve word variants: nho ((hieu quang) OR (hieu quan)) - hanh ((trinh cua) or (trinh luat)) nhung cong tan phan cau*.