Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
cua viet » ca viet, hoa viet, cua vat
va thanh » gia thanh, ban thanh, va tinh
ty hang » ly hang, ty xang, thi hang
hieu ve » hieu va, hieu van
ty nang » ky nang, ty xang, ly nang
su sach » so sach, vu sach
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: su sach ((ty nang) OR (ty hang)) o hoi. hieu ve ((pham duy) OR (pham duc)) va thanh dai cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) OR (ty hang)) o hoi. hieu ve ((pham duy) or (pham duc)) va thanh dai cua viet~".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) OR (ty hang)) o hoi. hieu ve ((pham duy) or (pham duc)) va thanh dai cua viet*.