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 ve » hieu va, hieu van
ve phan » va phan, ke phan, ve phat
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
cua tuc » cua tu, cua thuoc, luat tuc
cua duc » cua nuoc, cua quoc
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 ve phan duc va hanh va ((cua tuc) OR (cua duc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ((x hoi) OR (x ho)). hieu ve phan duc va hanh va ((cua tuc) OR (cua duc)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang ((x hoi) or (x ho)). hieu ve phan duc va hanh va ((cua tuc) OR (cua duc))".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ((x hoi) or (x ho)). hieu ve phan duc va hanh va ((cua tuc) OR (cua duc))*.