Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu xanh, nhieu tang
chieu sach » chinh sach, chiet tach, chieu xanh
hieu lang » hieu quang, nhieu tang, hieu van
dung cong » dung trong
trung va » truong va, trang va, trung ha
cong tan » cong tac, cong san, cong thanh
tan toan » tan tran, tap toan, van toan
toan cao » toan ban, toan tap
va dung » van dung, va duong, vat dung

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: hoc ((hieu lang) OR (((chieu sach) OR (chieu sang)))) - thanh trung va dung cong tan toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu lang) or (((chieu sach) OR (chieu sang)))) - thanh trung va dung cong tan toan cao~".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu lang) or (((chieu sach) OR (chieu sang)))) - thanh trung va dung cong tan toan cao*.