Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
hieu quang » thieu quang, hieu quan, hieu qua
thanh dung » thanh duong, thanh tung, thanh hung
dung quang » dang quang, dung quan, luong quang
quang dung » quang trung, ung dung, cuong dung
dung cong » dung trong
cong ban » cong bang, cong san, cong tan
ban phan » ban phap, van phan, ban than
phan dau » phan tu, hang dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((((chieu sang) or (hieu quang))) or (chinh sach)) - thanh dung quang dung cong ban phan dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((((chieu sang) OR (hieu quang))) OR (chinh sach)) - thanh dung quang dung cong ban phan dau.
• Adding a wildcard symbol may retrieve word variants: hoc ((((chieu sang) or (hieu quang))) or (chinh sach)) - thanh dung quang dung cong ban phan dau*.