Perhaps you should try some spelling variations:
su sach » so sach, vu sach
ky tang » ky dang, kho tang, ky trong
qua cau » quan cau, qua cac, qua ca
cau loc » hau loc, cau hoc, cau luc
danh vi » hanh vi, dinh vi, danh va
danh di » danh du, xanh di, danh dien
loc va » hoc va, luc va
thiet » thieu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky tang) OR (ky nang)) xa hoi. hieu qua cau loc va ((danh vi) OR (danh di)) va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky tang) or (ky nang)) xa hoi. hieu qua cau loc va ((danh vi) OR (danh di)) va thiet~".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky tang) or (ky nang)) xa hoi. hieu qua cau loc va ((danh vi) OR (danh di)) va thiet*.