Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
thai cua » than cua, tai cuc, tri cua
su sach » so sach, vu sach
duc van » duc va, duc tan, duc manh
luc van » luoc van, luu van, luc va
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
ro hai » co hai, so hai, do hai
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 sach 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 sach ky nang ((ro hai) OR (o hai)). hieu ve cac ((luc van) OR (duc van)) hanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach 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 sach ky nang ((ro hai) OR (o hai)). hieu ve cac ((luc van) or (duc van)) hanh thai cua tre*.