Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu cua » hieu qua, dieu cua, bieu cua
cua luat » quy luat
luat tuc » luat thue
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

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 lang xa hoi. hieu cua luat tuc ((va tinh) or (may tinh)) doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. hieu cua luat tuc ((va tinh) OR (may tinh)) doi cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. hieu cua luat tuc ((va tinh) or (may tinh)) doi cua tre*.