Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cac toc » cac toi, cac nuoc, cac thoi
via cua » gia cua, gian cua, giau cua
va hanh » van hanh, va thanh, va danh
cac tuc » cac tu, cac tac, cac nuoc
y nang » ky nang, ly nang, v nang
va cua » va chua, ca cua, ma cua
x hoi » xa hoi, o hoi, x ho

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: su sach y nang x hoi. hieu van ((cac tuc) OR (cac toc)) va hanh ((va cua) OR (via cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. hieu van ((cac tuc) or (cac toc)) va hanh ((va cua) OR (via cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. hieu van ((cac tuc) or (cac toc)) va hanh ((va cua) OR (via cua)) tre*.