Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
cam thuc » nam thuc, cam thu, can thuc
ban hanh » ban hang
hanh vai » hanh vi, hanh va, hanh tai
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet

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