Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
cua tre » cua te, cuu tre, cua triet
vu nang » vuc nang, va nang, vu dang
loc va » luc va
dan di » danh di, dan da, dan de
di cua » dai cua, doi cua, de cua
va cam » va cham, va cac, va cao
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 (doc sach)) vu nang x hoi. lieu va cam ((loc va) OR (hoc va)) dan di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) vu nang x hoi. lieu va cam ((loc va) OR (hoc va)) dan di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) vu nang x hoi. lieu va cam ((loc va) OR (hoc va)) dan di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) vu nang x hoi. lieu va cam ((loc va) OR (hoc va)) dan di cua tre*.