Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu quang » thieu quang, hieu quan, hieu qua
duong cong » dung cong, luong cong, duong trong
cong thanh » dong thanh, cong trinh, cong tan
hieu lang » chieu sang, nhieu tang, hieu van
trung cua » truong cua, trung tuan, trung cap
cua duong » cua dong, cua huong, qua duong
tran chau » tranh chap, tran huu
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((hieu lang) OR (hieu quang)) - thanh trung cua duong cong thanh ((tran chau) or (toan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu lang) OR (hieu quang)) - thanh trung cua duong cong thanh ((tran chau) OR (toan tap)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu lang) OR (hieu quang)) - thanh trung cua duong cong thanh ((tran chau) or (toan tap))".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu lang) OR (hieu quang)) - thanh trung cua duong cong thanh ((tran chau) or (toan tap))*.