Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » thong cong, hang cong, nhung don
thanh cua » tranh cua, than cua, thanh cha
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
hanh cua » manh cua, hang cua, hanh sua
tan gian » tran gian, dan gian, van gian
gian man » gian dan, gian lan, gian van

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

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