Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
hieu van » hieu va, thien van, lieu va
thai cua » than cua, tai cuc, tri cua
van bac » van ban, van bao, van hac
duc van » duc va, duc tan, duc manh
xuc ban » duc ban, cuc ban, quoc ban
tu sach » thu sach, su sach, te sach
hoc hai » hoc dai, hoc bai, hoc tai
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ho hai » pho hai, cho hai, ho hap

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 y nang ((ho hai) or (hoc hai)). hieu van bac ((xuc ban) or (duc van)) hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((ho hai) OR (hoc hai)). hieu van bac ((xuc ban) OR (duc van)) hanh thai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((ho hai) or (hoc hai)). hieu van bac ((xuc ban) or (duc van)) hanh thai cua tre*.