Perhaps you should try some spelling variations:
vat cua » mat cua, bat cua, dat cua
van vat » van chat, nhan vat
cac dai » cac dan, cac bai, can dai
sach ky » sach y, sach ty, sach kem
hieu va » lieu va, hieu qua
cac dac » cac dan, cac bac, cac tac
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
da van » dao van, dam van, va van

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)) lang xa hoi. hieu va ((cac dac) or (cac dai)) da van vat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) lang xa hoi. hieu va ((cac dac) OR (cac dai)) da van vat cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) OR (sac ky)) lang xa hoi. hieu va ((cac dac) or (cac dai)) da van vat cua tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) OR (sac ky)) lang xa hoi. hieu va ((cac dac) or (cac dai)) da van vat cua tre*.