Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
duc manh » suc manh, duc minh, duc tan
dau tien » van tien
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
hai dau » han dau, hai dan, hai hau
y nang » ky nang, ly nang, v nang
ve cam » ve cham, ve cac, va cam
o hoi » co hoi, o hoc, o hai

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 y nang ((x ho) OR (o hoi)). hieu ve cam ((duc anh) OR (duc manh)) thanh hai dau tien~.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x ho) or (o hoi)). hieu ve cam ((duc anh) or (duc manh)) thanh hai dau tien*.