Perhaps you should try some spelling variations:
van thanh » van tuan
ban thanh » ban hanh, ban hang
hanh vai » hanh vi, hanh va, hanh tai
van hanh » ban hanh, van anh, van ban
vai cua » dai cua, hai cua, lai cua
luc van » luoc van, luu van, duc van
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, mang may
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2

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 v ((nang ma) OR (nang cao)) hoi. hieu ((van thanh) or (ban thanh)) luc van hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach v ((nang ma) OR (nang cao)) hoi. hieu ((van thanh) OR (ban thanh)) luc van hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v ((nang ma) OR (nang cao)) hoi. hieu ((van thanh) or (ban thanh)) luc van hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach v ((nang ma) OR (nang cao)) hoi. hieu ((van thanh) or (ban thanh)) luc van hanh vai cua tre*.