Perhaps you should try some spelling variations:
tinh vai » tinh va, tinh hai, tinh bai
vai cua » dai cua, hai cua, lai cua
cuu ban » cuu van, cuu san, cuu nang
hieu ve » hieu va, hieu van
sach ky » sach y, sach ty, sach kem
dang xa » dang xay, lang xa, dang ha
cua tre » cua te, cuu tre, cua triet
ve cac » va cac, vien cac
sac ky » cac ky, sai ky

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 ky) or (sac ky)) dang xa hoi. hieu ve cac ((cuu ban) OR (cua ban)) tinh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) dang xa hoi. hieu ve cac ((cuu ban) OR (cua ban)) tinh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sac ky)) dang xa hoi. hieu ve cac ((cuu ban) OR (cua ban)) tinh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) dang xa hoi. hieu ve cac ((cuu ban) OR (cua ban)) tinh vai cua tre*.