Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
xanh tai » hanh tai, anh tai, vanh tai
tu sach » su sach, te sach, tu cach
tai cuu » tai cuc, tai buu, tai cua
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
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: ((tu sach) OR (thu sach)) ky nang ((o hoi) OR (o hoc)). hieu va cac duc va xanh tai cuu tre~.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang ((o hoi) or (o hoc)). hieu va cac duc va xanh tai cuu tre*.