Perhaps you should try some spelling variations:
sach ky » sac ky, sach ty, sach kem
lang xa » lang ha, dang xay, lang van
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan tai, dan vat
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
va nam » ha nam, va nay
va dan » ca dan, va dao, va dau

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

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