Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, hieu lang
nhung cong » thong cong, hang cong, nhung don
hieu quan » hieu qua, lieu quan, thien quan
trung cua » truong cua, trung tuan, trung cap
dung cong » dung trong
dan phan » doan phan, dan chan, van phan

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: ho ((chieu sang) OR (hieu quan)) - thanh trung cua ((nhung cong) OR (dung cong)) dan phan tu~.
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) or (hieu quan)) - thanh trung cua ((nhung cong) or (dung cong)) dan phan tu*.