Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
cham sao » cham vao, cham soc, nam sao
ban hanh » ban hang
ky tang » ky nang, ky dang, kho tang
mai hoi » mai khoi, dai hoi, lai hoi
sao ban » tao ban, cao bang, tao bang
vai cua » dai cua, hai cua, lai cua
ma hoi » xa hoi, ma hoa, me hoi
vi cua » di cua

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: tu cac ky tang ((ma hoi) OR (mai hoi)). hieu van cham sao ban hanh ((vi cua) OR (vai cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky tang ((ma hoi) or (mai hoi)). hieu van cham sao ban hanh ((vi cua) OR (vai cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: tu cac ky tang ((ma hoi) or (mai hoi)). hieu van cham sao ban hanh ((vi cua) OR (vai cua)) tre*.