Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, nhieu tang
duong cong » dung cong, luong cong, duong trong
hieu lang » hieu quang, nhieu tang, hieu van
trung can » trung cap, trung van, trong can
can duong » canh duong, con duong, van duong
cong luan » tong luan, cong tuan, dong luan

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 lang)) - thanh trung can duong cong luan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sang) OR (hieu lang)) - thanh trung can duong cong luan van ban.
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sang) or (hieu lang)) - thanh trung can duong cong luan van ban*.