Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hoc thien » hoc hien, hoc thieu, hoc thiet
trang van » tran van, trang va, trong van
thanh cau » thanh chau, thanh mau, nhanh cau
tram van » tran van, tam van, tranh van
cong van » cong vang, song van, cong tan
cong san » cong tac

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 thien hach - hanh ((tram van) OR (trang van)) dung ((cong van) OR (cong san)) thanh cau~.
• Adding a wildcard symbol may retrieve word variants: hoc thien hach - hanh ((tram van) or (trang van)) dung ((cong van) or (cong san)) thanh cau*.