Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
vu sach » vu bach, su sach
qua cam » qua cham, qua cac, qua ca
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
cam tu » cam thu, nam tu, dam tu
vi cua » vai cua, di cua
x hoi » o hoi, x ho, 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 sach) or (vu khach)) ky nang ((x hoi) OR (xa hoi)). hieu qua cam tu va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (vu khach)) ky nang ((x hoi) OR (xa hoi)). hieu qua cam tu va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) or (vu khach)) ky nang ((x hoi) OR (xa hoi)). hieu qua cam tu va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) or (vu khach)) ky nang ((x hoi) OR (xa hoi)). hieu qua cam tu va hanh vi cua tre*.