Perhaps you should try some spelling variations:
nang hang » nang sang, hang hang, cang thang
cong vang » cong lang, cong quang, cong ngang
vang tuan » van tuan, vong tuan, quang tuan
hoc hieu » hoc thieu, hoc hien, hoc dieu
doc hieu » toc thieu, hoc thieu, hoc hien
vat dung » van dung, va dung, viet dung
tuan cau » toan cau, quan cau, tuan cu

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 hieu) OR (doc hieu)) manh - nang hang ((va ung) OR (vat dung)) cong vang tuan cau~.
• Adding a wildcard symbol may retrieve word variants: ((hoc hieu) or (doc hieu)) manh - nang hang ((va ung) or (vat dung)) cong vang tuan cau*.