Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
thanh tung » thanh cong
chong cong » cong cong, thong cong, cuong cong
hieu lang » chieu sang, nhieu tang, hieu van
cua chong » cua cong, cua chung, cua khong
tung cua » trung cua, tuong cua, dung cua
cong tan » cong tac, cong san, cong thanh
than ban » thanh ban, than man, nhuan ban
toan ban » van ban

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 lang) OR (hieu quang)) - thanh tung cua chong cong tan ((than ban) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu lang) OR (hieu quang)) - thanh tung cua chong cong tan ((than ban) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu lang) OR (hieu quang)) - thanh tung cua chong cong tan ((than ban) or (toan ban))".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu lang) OR (hieu quang)) - thanh tung cua chong cong tan ((than ban) or (toan ban))*.