Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu va » lieu va, hieu qua
di cua » dai cua, doi cua, de cua
dan di » danh di, dan da, dan de
loc va » hoc va
luc va » duc va, tuc va
va cam » va cham, va cac, va cao
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
cua te » cua tu
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 v nang ((x hoi) OR (o hoi)). hieu va cam ((luc va) or (loc va)) dan di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v nang ((x hoi) OR (o hoi)). hieu va cam ((luc va) OR (loc va)) dan di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v nang ((x hoi) OR (o hoi)). hieu va cam ((luc va) or (loc va)) dan di cua te".
• Adding a wildcard symbol may retrieve word variants: toc sach v nang ((x hoi) OR (o hoi)). hieu va cam ((luc va) or (loc va)) dan di cua te*.