Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
van cac » van hac, van cau, van bac
tai cua » thai cua, tai cuc, tri cua
duc ban » duc tan, duc van, dua ban
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, may nang
ho hai » hoc hai, pho hai, cho hai
v nang » va nang, vu nang, van nang

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