Perhaps you should try some spelling variations:
hinh thai » sinh thai, tinh thai, dinh thi
hanh thai » nhanh thai, hanh tai, anh thai
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cac xuc » cam xuc, cac nuoc, chat xuc
xuc ban » duc ban, cuc ban, quoc ban
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
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 sach ky nang o hai. ((hieu ve) OR (hieu van)) cac xuc ban ((hanh thai) or (hinh thai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hai. ((hieu ve) OR (hieu van)) cac xuc ban ((hanh thai) OR (hinh thai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hai. ((hieu ve) OR (hieu van)) cac xuc ban ((hanh thai) or (hinh thai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hai. ((hieu ve) OR (hieu van)) cac xuc ban ((hanh thai) or (hinh thai)) cua tre*.