Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh tai, hanh van
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
duc ban » duc tan, duc van, dua ban
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
y nang » ly nang, v nang, may nang
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho

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) or (ky nang)) x hoi. hieu ve cac duc ban ((hanh vai) OR (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (ky nang)) x hoi. hieu ve cac duc ban ((hanh vai) OR (hanh va)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) or (ky nang)) x hoi. hieu ve cac duc ban ((hanh vai) OR (hanh va)) cua tre*".