Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va cham » va chat, va tham
duoc va » nuoc va, duc va, duoc ma
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
loc va » hoc va, luc va
di cua » dai cua, doi cua, de cua
o hoi » co hoi, o hai, o hoa
o hoc » co hoc, mo hoc, so hoc

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

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