Perhaps you should try some spelling variations:
hieu luc » hieu luat, hieu qua
va thanh » gia thanh, ban thanh, va tinh
hieu vuc » hieu tuc, hieu thuc, hieu viec
va hanh » van hanh, va danh, ban hanh
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
ca viet » va viet, co viet, hoa viet
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
lai ca » lai cua, lai cam, loai ca

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 v nang xa hoi. ((hieu vuc) or (hieu luc)) nang luc ((va hanh) OR (va thanh)) lai ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v nang xa hoi. ((hieu vuc) OR (hieu luc)) nang luc ((va hanh) OR (va thanh)) lai ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v nang xa hoi. ((hieu vuc) or (hieu luc)) nang luc ((va hanh) OR (va thanh)) lai ca viet".
• Adding a wildcard symbol may retrieve word variants: su sach v nang xa hoi. ((hieu vuc) or (hieu luc)) nang luc ((va hanh) OR (va thanh)) lai ca viet*.