Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
lang di » lang dai, hang di, lang du
va lang » va nang, hoa lang
cao duc » dao duc, cao suc, giao duc
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, mang xa
va cao » va cac, va co, va dao
di cua » dai cua, doi cua, de cua

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) OR (nang ma)) hoi. hieu va cao duc va lang di cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) v ((nang xa) OR (nang ma)) hoi. hieu va cao duc va lang di cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) v ((nang xa) OR (nang ma)) hoi. hieu va cao duc va lang di cua tre*.