Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
cac thoi » cac toi, cac hop, cac tro
va thanh » gia thanh, va tinh, le thanh
mai hoi » mai khoi, dai hoi, lai hoi
van cac » van hac, van cau, van bac
cuu tre » cua tre, cau tren, cau treo
ma hoi » xa hoi, ma hoa, me hoi
vi cuu » vi luu, vinh cuu

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 nang ((ma hoi) OR (mai hoi)). hieu van cac thoi ((va thanh) OR (ban thanh)) vi cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky nang ((ma hoi) or (mai hoi)). hieu van cac thoi ((va thanh) OR (ban thanh)) vi cuu tre~".
• Adding a wildcard symbol may retrieve word variants: tu cac ky nang ((ma hoi) or (mai hoi)). hieu van cac thoi ((va thanh) OR (ban thanh)) vi cuu tre*.