Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
cam thuc » am thuc, nam thuc, cam thu
thuc ban » thuoc ban, thuc dan, thu ban
ban hanh » ban hang
hanh vai » hanh vi, hanh va, hanh tai
te sach » toc sach
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
x hoi » xa hoi, o hoi, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu khach) or (te sach)) ky nang ((x hoi) OR (x ho)). lieu va cam thuc ban hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu khach) OR (te sach)) ky nang ((x hoi) OR (x ho)). lieu va cam thuc ban hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu khach) or (te sach)) ky nang ((x hoi) OR (x ho)). lieu va cam thuc ban hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu khach) or (te sach)) ky nang ((x hoi) OR (x ho)). lieu va cam thuc ban hanh vai cua tre*.