Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
su triet » su viet, su tien
hieu van » hieu va, thien van, lieu va
ve triet » va trien
tang van » dang van, hoang van, trong van
sach ky » sac ky, sach y, sach ty
cac lap » cac lop, cac cap, cac tap
va hanh » van hanh, va thanh, va danh
nang xa » nang x, lang xa, nang ma
van cac » van hac, van cau, van bac
lap va » tap va

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