Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu sang » thieu khang, thieu quang, hieu lang
chieu sang » chieu sach, chieu xanh, hieu lang
trung cua » truong cua, trung tuan, trung cap
cua dung » cua dang, cua dong, qua dung
cong ban » cong bang, cong tan, cong dan
cong san » cong tac
hang lap » sang lap, hang la, hang tap

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 (chieu sang)) - thanh trung cua dung ((cong ban) OR (cong san)) hang lap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (chieu sang)) - thanh trung cua dung ((cong ban) OR (cong san)) hang lap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (chieu sang)) - thanh trung cua dung ((cong ban) OR (cong san)) hang lap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (chieu sang)) - thanh trung cua dung ((cong ban) OR (cong san)) hang lap*.