Perhaps you should try some spelling variations:
mai hoi » mai khoi, dai hoi, mai doi
lai hoi » dai hoi, lai hoa, lai roi
hieu ve » hieu va, hieu van
cac dac » cac dan, cac dai, cac bac
anh tri » anh thi, anh tai, thanh tri
cua tre » cua te, cuu tre, cua triet
su cac » tu cac, su cao, su can
ve cac » va cac, vien cac
dac va » duc va, day va, dat va
va anh » van anh, va danh, va hanh

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su cac ky nang ((mai hoi) OR (lai hoi)). hieu ve cac dac va anh tri cua tre~.
• Adding a wildcard symbol may retrieve word variants: su cac ky nang ((mai hoi) or (lai hoi)). hieu ve cac dac va anh tri cua tre*.