Perhaps you should try some spelling variations:
duoc hien » duoc thien, duoc dien, duoc bien
hien hanh » dieu hanh
trinh vat » trinh van, trinh luat, sinh vat
dung cong » dung trong
tranh va » tranh van, trang va, trinh va
cong van » cong vang, cong san, song van
van tan » van tuan, van ban, van tai
tan cau » toan cau, van cau, tan ca

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: duoc hien hanh - canh ((trinh vat) OR (tranh va)) dung cong van tan cau~.
• Adding a wildcard symbol may retrieve word variants: duoc hien hanh - canh ((trinh vat) or (tranh va)) dung cong van tan cau*.