Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
hanh dai » hanh tai, hanh dao, vanh dai
van cam » van nam, van lam, van cau
cam cua » ca cua, nam cua, cau cua
cua tre » cua te, cuu tre, dua tren
o hoi » co hoi, o hoc, o hoa
o hai » co hai, so hai, o lai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu cac ky nang ((o hoi) or (o hai)). hieu van cam cua ban hanh dai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky nang ((o hoi) OR (o hai)). hieu van cam cua ban hanh dai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky nang ((o hoi) or (o hai)). hieu van cam cua ban hanh dai ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu cac ky nang ((o hoi) or (o hai)). hieu van cam cua ban hanh dai ((cua tre) OR (cua triet))*.