Perhaps you should try some spelling variations:
phan duc » pham duc, phan tu, phan dau
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
hieu vi » hieu voi, hieu va, hieu ve
vi phan » va phan, vi pham, ve phan
hanh va » hanh vi
cua su » qua su
x hoi » xa hoi, o hoi, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang ((x hoi) or (x ho)). hieu vi phan duc va ((hanh va) OR (hang va)) cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ((x hoi) OR (x ho)). hieu vi phan duc va ((hanh va) OR (hang va)) cua su.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang ((x hoi) or (x ho)). hieu vi phan duc va ((hanh va) OR (hang va)) cua su".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ((x hoi) or (x ho)). hieu vi phan duc va ((hanh va) OR (hang va)) cua su*.