Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
danh dau » lanh dao, hang dau, danh tu
danh sai » dung sai, danh bat, hanh san
cua viet » ca viet, hoa viet, cua vat
song xa » song cua
sach ky » sac ky, sach y, sach ty
va pham » van pham, va phat, va phap
sang xa » lang xa, sang ma, mang xa
hieu va » lieu va, hieu qua

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