Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh va, hanh tai, hanh van
tuc ban » thuc ban, truc ban, tu ban
hac tuc » thac toc, thai tuc
sach ky » sach y, sach ty, sach kem
van hac » van hoc, van ha, van hai
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky

You may be able to get more results by adjusting your search query.

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