Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trung phai » trung phan, trung hai, trung phat
nhung cong » dung cong, thong cong, hang cong
cong thanh » dong thanh, cong trinh, cong tan
thanh tap » thanh tai, thanh tay, thanh tam
thanh lap » thanh san, phan lap, thanh hai
doc hieu » toc thieu, hoc thieu, hoc hien
trung ha » trung hoc, trung tam, trung cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu quang - thanh ((trung phai) or (trung ha)) nhung cong thanh ((thanh tap) OR (thanh lap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu quang - thanh ((trung phai) OR (trung ha)) nhung cong thanh ((thanh tap) OR (thanh lap)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu quang - thanh ((trung phai) or (trung ha)) nhung cong thanh ((thanh tap) OR (thanh lap))".
• Adding a wildcard symbol may retrieve word variants: doc hieu quang - thanh ((trung phai) or (trung ha)) nhung cong thanh ((thanh tap) OR (thanh lap))*.