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
va triet » va thiet, va trien, ve triet
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
luc van » luoc van, luu van, duc van
duc ban » duc tan, duc van, dua ban

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 xa hoi. hieu van nhan ((luc van) or (duc ban)) hanh vi ((va triet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. hieu van nhan ((luc van) OR (duc ban)) hanh vi ((va triet) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. hieu van nhan ((luc van) or (duc ban)) hanh vi ((va triet) or (su triet))*.