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 san, trong tan, trong quan
cao dung » cao dang, cao dong, cao ung
ban pha » ban phap, ban nha, ban ha
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 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 pha cau".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) OR (hieu lang)) - thanh trung cao dung trong ban pha cau*.