Perhaps you should try some spelling variations:
day nhanh » day thanh, duy nhanh, dac nhan
cam thuc » am thuc, nam thuc, cam thu
day hanh » day thanh, dao hanh, day manh
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
va cam » va cham, va cac, va cao
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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 (su sach)) ky nang o hoi. hieu va cam thuc ((day hanh) or (day nhanh)) doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu bach) OR (su sach)) ky nang o hoi. hieu va cam thuc ((day hanh) OR (day nhanh)) doi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((vu bach) or (su sach)) ky nang o hoi. hieu va cam thuc ((day hanh) or (day nhanh)) doi cua tre*.