Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
thai cua » than cua, tai cuc, tri cua
van hanh » van thanh, ban hanh, van anh
dac van » cac van, dao van, dam van
cac dac » cac dan, cac dai, cac bac
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach ty, sach kem
ve cac » va cac, vien cac
o hai » co hai, so hai, _ hai
o lai » o lao

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ky) or (sach y)) nang ((o hai) OR (o lai)). hieu ve cac dac van hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sach y)) nang ((o hai) OR (o lai)). hieu ve cac dac van hanh thai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sach y)) nang ((o hai) OR (o lai)). hieu ve cac dac van hanh thai cua tre*".