Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu sang » chieu sang, hieu quang, nhieu tang
hieu lang » chieu sang, hieu quang, nhieu tang
trung cao » truong cao, trung cap, trung co
trong ban » trong tan, trong quan, trong cac
trong san » trong cac, cong san, dong san
cao dung » cao dang, cao dong, cao ung
pha cau » phan cau, phap cau, pha cac

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 sang) or (hieu lang)) - thanh trung cao dung ((trong ban) OR (trong san)) pha cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (hieu lang)) - thanh trung cao dung ((trong ban) OR (trong san)) pha cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) or (hieu lang)) - thanh trung cao dung ((trong ban) OR (trong san)) pha cau".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu lang)) - thanh trung cao dung ((trong ban) OR (trong san)) pha cau*.