Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
va hanh » van hanh, va thanh, va danh
vai cua » dai cua, hai cua, lai cua
y nang » ky nang, ly nang, v nang
ve ban » te ban, ve bao, vu ban
va ban » van ban, va bai, va bao
bao va » bao ve, tao va, ban va
vi cua » di cua
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: so sach y nang x hoi. hieu ((ve ban) OR (va ban)) bao va hanh ((vi cua) or (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang x hoi. hieu ((ve ban) OR (va ban)) bao va hanh ((vi cua) OR (vai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang x hoi. hieu ((ve ban) OR (va ban)) bao va hanh ((vi cua) or (vai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach y nang x hoi. hieu ((ve ban) OR (va ban)) bao va hanh ((vi cua) or (vai cua)) tre*.