Perhaps you should try some spelling variations:
hieu luc » hieu luat, hieu qua
van hanh » van thanh, ban hanh, van anh
hieu cac » hieu va, hieu van, vien cac
hanh vai » hanh vi, hanh va, hanh tai
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cua tuc » cua duc, cua thuoc, luat tuc
co van » cao van, vo van, so van
cua tu » cua su, cua cu, cua te

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 ky nang xa hoi. hieu ((hieu cac) OR (hieu luc)) co van hanh vai ((cua tu) or (cua tuc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. hieu ((hieu cac) OR (hieu luc)) co van hanh vai ((cua tu) OR (cua tuc)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. hieu ((hieu cac) OR (hieu luc)) co van hanh vai ((cua tu) or (cua tuc))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. hieu ((hieu cac) OR (hieu luc)) co van hanh vai ((cua tu) or (cua tuc))*.