Perhaps you should try some spelling variations:
nhanh thai » nhanh thi, nhanh thanh, nhanh thang
thai cua » than cua, tai cuc, tri cua
su sach » so sach, vu sach
duc van » duc va, duc tan, duc manh
xuc van » luc van, xuc ban, thuc van
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
so hoc » co hoc, mo hoc, so hoa
o hoc » co hoc, mo hoc, y hoc

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 ((o hoc) OR (so hoc)). hieu ve cac ((xuc van) or (duc van)) nhanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((o hoc) OR (so hoc)). hieu ve cac ((xuc van) OR (duc van)) nhanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((o hoc) OR (so hoc)). hieu ve cac ((xuc van) or (duc van)) nhanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((o hoc) OR (so hoc)). hieu ve cac ((xuc van) or (duc van)) nhanh thai cua tre*.