Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
lang de » vang de, dang de, lang du
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
v nang » va nang, vu nang, van nang
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa
de cua » le cua, te cua, dieu cua
va cao » va cac, va co, va dao

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) v nang xa hoi. hieu va cao ((luc va) OR (tuc va)) lang de cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) v nang xa hoi. hieu va cao ((luc va) OR (tuc va)) lang de cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) v nang xa hoi. hieu va cao ((luc va) OR (tuc va)) lang de cua tre*.