Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
thanh tung » thanh cong
tuong cong » truong cong, tong cong, luong cong
hieu lang » chieu sang, hieu quang, nhieu tang
tap toan » tap doan, tap quan, bai toan
toan cao » toan ban, toan tap
tung va » trung va, tuong va, dung va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chieu xanh) or (hieu lang)) - thanh tung va ((tuong cong) OR (trong cong)) tap toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu xanh) OR (hieu lang)) - thanh tung va ((tuong cong) OR (trong cong)) tap toan cao*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu xanh) or (hieu lang)) - thanh tung va ((tuong cong) OR (trong cong)) tap toan cao*".