Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
hanh tang » hanh trang, anh tang, hanh mang
cua dung » cua dong, qua dung, cua rung
cua dang » cua cong, cua ban
cong tan » cong tac, cong san, cong thanh
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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 hien xanh - hanh tang ((cua dung) OR (cua dang)) cong tan ((toan cau) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien xanh - hanh tang ((cua dung) OR (cua dang)) cong tan ((toan cau) or (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - hanh tang ((cua dung) OR (cua dang)) cong tan ((toan cau) or (toan ban))*.