Perhaps you should try some spelling variations:
day dang » da dang, dai dang, day dan
cac thu » cach thuc, cac thoi
cua tre » cuu tre, cua triet, dua tren
hieu va » lieu va
dang de » dang deo, dung de, dang do
thu day » thuc day, thu da, thu dac
vu hai » su hai, vu ha
hai ky » thai ky, hoi ky, hai ly
nang o » nang co, nang ho, nang ro
cua te » cua tu
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 dang de ((cua tre) or (cua te))~.
• 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 dang de ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu hai ky nang o hoi. ((hieu va) OR (hieu qua)) cac thu day dang de ((cua tre) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: vu hai ky nang o hoi. ((hieu va) OR (hieu qua)) cac thu day dang de ((cua tre) or (cua te))*.