Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
thai cua » than cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
duc van » duc va, duc tan, duc manh
luc van » luoc van, luu van, luc va
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
xac ky » cac ky, sac ky, bac ky
ro hai » co hai, so hai, do hai
su xac » pu xac, su cac
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: su xac ky nang ((ro hai) or (o hai)). hieu ve cac ((luc van) or (duc van)) hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su xac ky nang ((ro hai) OR (o hai)). hieu ve cac ((luc van) OR (duc van)) hanh thai cua tre.
• Adding a wildcard symbol may retrieve word variants: su xac ky nang ((ro hai) or (o hai)). hieu ve cac ((luc van) or (duc van)) hanh thai cua tre*.