Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
dinh sai » dinh tai, danh sai, dinh hai
cua viet » ca viet, hoa viet, cua vat
sang xa » lang xa, sang ma, mang xa
song xa » song cua
va pham » van pham, va phat, va phap
va dinh » van dinh, va kinh, va tinh
sai cua » dai cua, hai cua, lai cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) OR (doc sach)) ky ((sang xa) or (song xa)) hoi. lieu va pham duc va dinh sai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky ((sang xa) OR (song xa)) hoi. lieu va pham duc va dinh sai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ky ((sang xa) or (song xa)) hoi. lieu va pham duc va dinh sai cua viet".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) ky ((sang xa) or (song xa)) hoi. lieu va pham duc va dinh sai cua viet*.