Perhaps you should try some spelling variations:
thieu quang » hieu quang, thien quan, trien quang
thieu sang » chieu sang, thieu khang, hieu lang
trong quan » thong quan, tong quan, thong quang
thong cong » trong cong, tong cong, thong thong
cong quang » luong quang, thong quang, duong quang
quang chat » quang chan, quang phat, quang cao
chat cao » chat co, chat cho, chat bao

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 sang) OR (thieu quang)) - hanh ((trong quan) or (truong dai)) thong cong quang chat cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu quang)) - hanh ((trong quan) OR (truong dai)) thong cong quang chat cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu quang)) - hanh ((trong quan) or (truong dai)) thong cong quang chat cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu quang)) - hanh ((trong quan) or (truong dai)) thong cong quang chat cao*.