Perhaps you should try some spelling variations:
qua ban » cua ban, qua quan
duc ban » duc tan, duc van, dua ban
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
y nang » ky nang, ly nang, v nang
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai
vi ve » va ve, ve ve, vi he
gi ve » gia ve, gi de, gi he

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang o hoi. hieu ve cac ((duc ban) or (qua ban)) hanh ((vi ve) OR (gi ve)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang o hoi. hieu ve cac ((duc ban) OR (qua ban)) hanh ((vi ve) OR (gi ve)) triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang o hoi. hieu ve cac ((duc ban) or (qua ban)) hanh ((vi ve) OR (gi ve)) triet*".