Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
cao luc » bao luc, cao duc, cao suc
hieu va » lieu va, hieu qua
di cua » dai cua, doi cua, de cua
va dau » va dao
va dan » ca dan, va dao, va dap
va cao » va cac, va co, va dao
v nang » va nang, vu nang, van nang
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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 (hoc sach)) v nang x hoi. hieu va cao luc ((va dan) or (va dau)) di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) v nang x hoi. hieu va cao luc ((va dan) OR (va dau)) di cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) v nang x hoi. hieu va cao luc ((va dan) or (va dau)) di cua te*".