Perhaps you should try some spelling variations:
hoc thieu » hoc hien
than tinh » thanh tinh, than kinh, thai tinh
trong dan » trong dang, trong tan, trong ban
trong san » trong cac, cong san, dong san
tinh cua » trinh cua, sinh cua, tinh chat
cua dong » chua dong, cua cong, cua dang
toan cau » toan cao, toan ban, toan 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: ((hoc thieu) OR (toc thieu)) xanh - than tinh cua dong ((trong dan) OR (trong san)) toan cau~.
• Adding a wildcard symbol may retrieve word variants: ((hoc thieu) or (toc thieu)) xanh - than tinh cua dong ((trong dan) or (trong san)) toan cau*.