Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
buu tre » cuu tre
va nam » van nam, ha nam
va nay » va ngay, va cay
va dau » va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky lang xa hoi. hieu ((va nam) or (va nay)) thuc ((va dau) or (ca dao)) tai buu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky lang xa hoi. hieu ((va nam) OR (va nay)) thuc ((va dau) OR (ca dao)) tai buu tre.
• Adding a wildcard symbol may retrieve word variants: doc sach ky lang xa hoi. hieu ((va nam) or (va nay)) thuc ((va dau) or (ca dao)) tai buu tre*.