Perhaps you should try some spelling variations:
chieu sang » chieu xanh, hieu lang, nhieu tang
chieu sach » chinh sach, chiet tach, chieu xanh
luan dang » luan nang, luan danh, luan tang
luan dong » luan cong, quan dong, luan nong
anh tang » anh bang, anh dang, anh nang
cong tac » cong ty
tac nhan » tao nhan, cac nhan, dac nhan
nhan cau » nhanh cau, phan cau, nhan sau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sang) OR (chieu sach)) - anh tang ((luan dang) OR (luan dong)) cong tac nhan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sang) OR (chieu sach)) - anh tang ((luan dang) or (luan dong)) cong tac nhan cau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sang) OR (chieu sach)) - anh tang ((luan dang) or (luan dong)) cong tac nhan cau*.