Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, nhieu tang
trung tuan » trung thanh, tran tuan, truong thanh
hieu lang » hieu quang, nhieu tang, hieu van
dang cong » dung cong
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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: doi ((hieu lang) OR (chieu sang)) - hanh ((trung tuan) OR (trung tam)) dang cong dan than cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((hieu lang) OR (chieu sang)) - hanh ((trung tuan) or (trung tam)) dang cong dan than cau~".
• Adding a wildcard symbol may retrieve word variants: doi ((hieu lang) OR (chieu sang)) - hanh ((trung tuan) or (trung tam)) dang cong dan than cau*.