Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, anh thai
hanh tai » thanh tai, hang tai, han tai
cua tre » cua te, cuu tre, cua triet
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
dang xa » dang xay, lang xa, dang va
dang ha » dong ha, dung ha, lang ha
tai ky » thai ky, trai ky, sai ky
ve cac » va cac, vien cac
su tai » su thi, tu tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su tai ky ((dang xa) or (dang ha)) hoi. hieu ve cac duc tan ((hanh thai) or (hanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su tai ky ((dang xa) OR (dang ha)) hoi. hieu ve cac duc tan ((hanh thai) OR (hanh tai)) cua tre.
• Adding a wildcard symbol may retrieve word variants: su tai ky ((dang xa) or (dang ha)) hoi. hieu ve cac duc tan ((hanh thai) or (hanh tai)) cua tre*.