Perhaps you should try some spelling variations:
thanh thanh » nhanh thanh, thanh toan, thanh phan
chieu sang » chieu sach, chieu xanh, nhieu tang
cong thanh » dong thanh, cong trinh, cong tan
hieu lang » hieu quang, nhieu tang, hieu van
trong xay » trong cac, trong ca, trong san
dung cong » dung trong
thanh cac » hanh cac, thanh bac, thanh ca

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 (chieu sang)) - thanh ((trong xay) or (thong xay)) dung cong thanh thanh cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu lang) OR (chieu sang)) - thanh ((trong xay) OR (thong xay)) dung cong thanh thanh cac*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu lang) OR (chieu sang)) - thanh ((trong xay) or (thong xay)) dung cong thanh thanh cac*".