Perhaps you should try some spelling variations:
vai cua » dai cua, hai cua, lai cua
dan vai » dan va, dan tai, dan vat
sach ky » sach y, sach ty, sach kem
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
ve cac » va cac, vien cac
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) OR (sac ky)) nang xa hoi. hieu ve cac ((xuc va) or (luc va)) dan vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) nang xa hoi. hieu ve cac ((xuc va) OR (luc va)) dan vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) OR (sac ky)) nang xa hoi. hieu ve cac ((xuc va) or (luc va)) dan vai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) OR (sac ky)) nang xa hoi. hieu ve cac ((xuc va) or (luc va)) dan vai cua tre*.