Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
tang luan » dung luan
luan dang » luan nang, luan danh, luan dong
dang cong » dung cong
nhanh cau » nhanh cay, thanh chau, nhanh ha
anh tang » anh bang, anh dang, anh nang
cong cac » cuong cac, cong tac, cong cau
nhan cau » phan cau, nhan sau, nhin cau

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 ((thieu sang) OR (thieu khang)) - anh tang luan dang cong cac ((nhan cau) OR (nhanh cau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu khang)) - anh tang luan dang cong cac ((nhan cau) or (nhanh cau))~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu khang)) - anh tang luan dang cong cac ((nhan cau) or (nhanh cau))*.