Perhaps you should try some spelling variations:
hien nhanh » hien hanh, thien thanh, tien thanh
hanh hang » thanh hang, hang hang, hanh han
vat dung » van dung, viet dung, mat duong
cong van » cong vang, cong san, song van
va dung » van dung, va duong, va ung
van tan » van tuan, van ban, van tai
tan ca » tan cua, tang ca, dan ca

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien nhanh - hanh hang ((va dung) or (vat dung)) cong van tan ca~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien nhanh - hanh hang ((va dung) OR (vat dung)) cong van tan ca*.