Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
qua dau » qua da, qua bau, qua dan
duc ban » duc tan, dua ban, duc man
duc van » duc va, duc tan, duc manh
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua
de cua » le cua, te cua, dieu cua
x hoi » xa hoi, o hoi, x ho

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 hoi. hieu qua dau ((duc ban) OR (duc van)) hanh ((vi cua) OR (de cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang x hoi. hieu qua dau ((duc ban) OR (duc van)) hanh ((vi cua) or (de cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang x hoi. hieu qua dau ((duc ban) OR (duc van)) hanh ((vi cua) or (de cua)) tre*.