Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
va thanh » gia thanh, va tinh, le thanh
va triet » va thiet, va trien, ve triet
tu sach » thu sach, su sach, te sach
ty nang » ty xang, ty hang, ly nang
hieu va » lieu va, hieu qua
vinh va » vinh van, tinh va, sinh va
va nam » van nam, ha nam, va nay
o hoi » co hoi, o hoc, o hai

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 ((ty nang) OR (ky nang)) o hoi. hieu va nam cua ((va thanh) or (ban thanh)) vinh va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ky nang)) o hoi. hieu va nam cua ((va thanh) OR (ban thanh)) vinh va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ky nang)) o hoi. hieu va nam cua ((va thanh) or (ban thanh)) vinh va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) OR (ky nang)) o hoi. hieu va nam cua ((va thanh) or (ban thanh)) vinh va triet*.