Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu tinh, hieu manh
chieu sang » chieu sach, nhieu tang
thanh tung » thanh cong
hieu lang » hieu quang, nhieu tang, hieu van
dung cong » dung trong
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan cao » toan ban, toan tap
tung va » trung va, tuong va, dung va
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: ho ((((chieu xanh) OR (chieu sang))) OR (hieu lang)) - thanh tung va dung cong tap toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((((chieu xanh) OR (chieu sang))) or (hieu lang)) - thanh tung va dung cong tap toan cao~".
• Adding a wildcard symbol may retrieve word variants: ho ((((chieu xanh) OR (chieu sang))) or (hieu lang)) - thanh tung va dung cong tap toan cao*.