Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va triet » va thiet, va trien, ve triet
va chat » van chat, va phat, cao chat
y nang » ky nang, ly nang, v nang
doc va » duoc va, hoc va, duc va
loc va » hoc va, luc va
kem va » kiem va, kiem van
o hoc » co hoc, mo hoc, so hoc
o hoi » co hoi, o hai, o hoa

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 chat ((doc va) or (loc va)) hanh kem va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ((o hoi) OR (o hoc)). lieu va chat ((doc va) OR (loc va)) hanh kem va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y nang ((o hoi) OR (o hoc)). lieu va chat ((doc va) or (loc va)) hanh kem va triet".
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ((o hoi) OR (o hoc)). lieu va chat ((doc va) or (loc va)) hanh kem va triet*.