Perhaps you should try some spelling variations:
danh thanh » dinh thanh, dang thanh, nhanh thanh
thanh vai » thanh hai, thanh van, thanh tai
cua viet » ca viet, hoa viet, cua vat
cac sach » cao sach, cau sach, dac sac
cac cach » cai cach, cuoc cach, va cach
vai cua » dai cua, hai cua, lai cua
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ty nang) or (ty hang)) xa hoi. hieu ve ((cac sach) OR (cac cach)) danh thanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty nang) OR (ty hang)) xa hoi. hieu ve ((cac sach) OR (cac cach)) danh thanh vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) or (ty hang)) xa hoi. hieu ve ((cac sach) OR (cac cach)) danh thanh vai cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) or (ty hang)) xa hoi. hieu ve ((cac sach) OR (cac cach)) danh thanh vai cua viet*.