Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
chieu tinh » trieu tinh, lieu tinh, chau tinh
thanh tung » thanh cong
dung cong » dung trong
tung cua » trung cua, tuong cua, dung cua
cua dung » cua dang, cua dong, qua dung
bai toan » bai tap
bi tan » bui tan, b tan, bi tai

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 ((thieu xanh) OR (chieu tinh)) - thanh tung cua dung cong ((bi tan) OR (bai toan)) tap~.
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) or (chieu tinh)) - thanh tung cua dung cong ((bi tan) or (bai toan)) tap*.