Perhaps you should try some spelling variations:
cham luc » cham soc, nhan luc, cham cuu
qua cham » qua hai, qua cac, va cham
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
doi cau » doi dau, doi ca, doi cay
luc va » duc va, tuc va, loc va
di cau » da cau, diem cau
x hoi » xa hoi, o hoi, 5 hoi

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 nang ((x hoi) OR (x ho)). hieu qua cham luc va hanh ((doi cau) OR (di cau)) tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((x hoi) or (x ho)). hieu qua cham luc va hanh ((doi cau) OR (di cau)) tren~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((x hoi) or (x ho)). hieu qua cham luc va hanh ((doi cau) OR (di cau)) tren*.