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
cua tre » cua te, cuu tre, cua triet
duc van » duc va, duc tan, duc manh
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 » 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) OR (va cac)) duc van hanh thai 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) OR (va cac)) duc van hanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su tai ky ((dang xa) or (dang ha)) hoi. hieu ((ve cac) OR (va cac)) duc van hanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: su tai ky ((dang xa) or (dang ha)) hoi. hieu ((ve cac) OR (va cac)) duc van hanh thai cua tre*.