Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
te sach » toc sach
xanh di » danh di, vanh dai, xanh tai
va xanh » va danh, va hanh, va anh
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
di cuu » di cau, di cua, dinh cuu
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.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (thu sach)) ky nang ((o hoi) OR (o hoc)). hieu va cac duc va xanh di cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (thu sach)) ky nang ((o hoi) OR (o hoc)). hieu va cac duc va xanh di cuu tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (thu sach)) ky nang ((o hoi) OR (o hoc)). hieu va cac duc va xanh di cuu tre*.