Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
va cham » va chat, va tham
y nang » ky nang, ly nang, v nang
luc va » duc va, tuc va
loc va » hoc va
vi cau » va cau, ve cau, di cau
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang ((x hoi) or (o hoi)). lieu va cham ((luc va) OR (loc va)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (o hoi)). lieu va cham ((luc va) OR (loc va)) hanh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((x hoi) or (o hoi)). lieu va cham ((luc va) OR (loc va)) hanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) or (o hoi)). lieu va cham ((luc va) OR (loc va)) hanh vi cau tren*.