Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
tuong cua » truong cua, huong cua, thong cua
dung cong » dung trong
ho chieu » theo chieu, hoc thieu, doi chieu
tung cua » trung cua, dung cua, tang cua
tan toan » tan tran, tap toan, van toan
bai toan » bai tap

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 - thanh ((tung cua) OR (tuong cua)) dung cong ((tan toan) OR (bai toan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho chieu xanh - thanh ((tung cua) OR (tuong cua)) dung cong ((tan toan) or (bai toan)) cau~".
• Adding a wildcard symbol may retrieve word variants: ho chieu xanh - thanh ((tung cua) OR (tuong cua)) dung cong ((tan toan) or (bai toan)) cau*.