Perhaps you should try some spelling variations:
thien van » thi van
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, lieu va, hieu ve
vai cua » dai cua, hai cua, lai cua
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va
ma hoi » mai hoi, xa hoi, ma hoa

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 ty nang ma hoi. ((hieu van) or (thien van)) cam ((xuc va) or (thuc vat)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ma hoi. ((hieu van) OR (thien van)) cam ((xuc va) OR (thuc vat)) hanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ma hoi. ((hieu van) or (thien van)) cam ((xuc va) or (thuc vat)) hanh vai cua tre*.