Perhaps you should try some spelling variations:
thieu quang » hieu quang, trien quang, hieu quan
thien quan » trien quang, lien quan, thien van
hoang cao » hoang bao, hoang hao, hoang thao
dung cong » dung trong
hang cao » nang cao, hang ca, hang cau
cong tan » cong tac, cong san, cong thanh
tran tap » toan tap, tran tan, tran tuan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu quang) or (thien quan)) - hanh ((hang cao) OR (hoang cao)) dung cong tan tran tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu quang) OR (thien quan)) - hanh ((hang cao) OR (hoang cao)) dung cong tan tran tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu quang) or (thien quan)) - hanh ((hang cao) OR (hoang cao)) dung cong tan tran tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu quang) or (thien quan)) - hanh ((hang cao) OR (hoang cao)) dung cong tan tran tap*.