Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va hanh » van hanh, va thanh, va danh
cau luc » cau truc, cau phuc
hieu va » lieu va, hieu qua
hieu ve » hieu van
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
luc va » duc va, tuc va, loc va
vi cua » vai cua, di cua
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 ((x hoi) OR (o hoi)). ((hieu ve) or (hieu va)) cau luc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ((x hoi) OR (o hoi)). ((hieu ve) OR (hieu va)) cau luc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y nang ((x hoi) OR (o hoi)). ((hieu ve) or (hieu va)) cau luc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ((x hoi) OR (o hoi)). ((hieu ve) or (hieu va)) cau luc va hanh vi cua tre*.