Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach vu » sach va, sach tu, sach uu
vu nang » vuc nang, va nang, vu dang
dan dai » dat dai, can dai, dan dat
cua tre » cua te, cuu tre, cua triet
va cao » va co, va dao, va bao
luc va » duc va, tuc va, loc va
va dan » ca dan, va dao, va dau
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 vu nang x hoi. hieu ((va cao) or (va cac)) luc va dan dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach vu nang x hoi. hieu ((va cao) OR (va cac)) luc va dan dai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach vu nang x hoi. hieu ((va cao) or (va cac)) luc va dan dai cua tre*.