Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
luc van » luoc van, luu van, duc van
cam luc » cam xuc, cau luc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
lang ha » long ha
nang ma » tang ma, sang ma, nang cao

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 ma) or (lang ha)) hoi. ((hieu ve) or (hieu van)) cam luc van hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang ma) OR (lang ha)) hoi. ((hieu ve) OR (hieu van)) cam luc van hanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang ma) or (lang ha)) hoi. ((hieu ve) or (hieu van)) cam luc van hanh vai cua tre*.