Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
dau tien » van tien
duc manh » suc manh, duc anh, duc minh
dau tren » dat tren, dau tieng, dau trong
duc danh » duc anh, duc hanh, duc dan
hieu ve » hieu va, hieu van
tu sach » thu sach, su sach, te sach
ve cam » ve cham, ve cac, va cam
y nang » ky nang, ly nang, v nang
nang o » nang co, nang ho, nang ro
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 o hoi. hieu ve cam ((duc danh) OR (duc manh)) thanh hai ((dau tren) OR (dau tien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang o hoi. hieu ve cam ((duc danh) or (duc manh)) thanh hai ((dau tren) OR (dau tien))~".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang o hoi. hieu ve cam ((duc danh) or (duc manh)) thanh hai ((dau tren) OR (dau tien))*.