Perhaps you should try some spelling variations:
cac thu » cach thuc, cac thoi
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va
day dan » day danh, dao dan, cay dan
thu day » thuc day, thu da, thu dac
dan de » dan den, dang de, van de
vu hai » su hai, vu ha
hai ky » thai ky, hoi ky, hai ly
nang o » nang co, nang ho, nang ro
cua tu » cua tuc, cua su, cua cu
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 hai ky nang o hoi. ((hieu va) or (hieu qua)) cac thu day dan de ((cua tre) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu hai ky nang o hoi. ((hieu va) OR (hieu qua)) cac thu day dan de ((cua tre) OR (cua tu)).
• Adding a wildcard symbol may retrieve word variants: vu hai ky nang o hoi. ((hieu va) or (hieu qua)) cac thu day dan de ((cua tre) or (cua tu))*.