Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
hanh vai » hanh vi, hanh va, hanh tai
cua tre » cua te, cuu tre, cua triet
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
hoc hoi » hoc khoi, hoc hoa, hoc noi
doc hoi » duoc hoi, doc hai, doi hoi
va cam » va cham, va cac, va cao
cam tu » cam thu, nam tu, dam tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu bach) or (vu khach)) ky nang ((doc hoi) OR (hoc hoi)). hieu va cam tu va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu bach) OR (vu khach)) ky nang ((doc hoi) OR (hoc hoi)). hieu va cam tu va hanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu bach) or (vu khach)) ky nang ((doc hoi) OR (hoc hoi)). hieu va cam tu va hanh vai cua tre*".