Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van nhan » van phan, van thanh, danh nhan
nhan luc » nang luc
ban hanh » ban hang
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
luc ban » duc ban, cuc ban, luc bat
su viet » so viet
x hoi » o hoi, x ho, 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: thu sach ky nang ((x hoi) OR (xa hoi)). hieu van nhan luc ban hanh vi ((va triet) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((x hoi) OR (xa hoi)). hieu van nhan luc ban hanh vi ((va triet) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((x hoi) OR (xa hoi)). hieu van nhan luc ban hanh vi ((va triet) or (su viet))".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((x hoi) OR (xa hoi)). hieu van nhan luc ban hanh vi ((va triet) or (su viet))*.