Perhaps you should try some spelling variations:
ban hanh » ban hang
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
sach vu » sach va, sach tu, sach uu
tu sach » thu sach, su sach, te sach
mai hoi » mai khoi, dai hoi, lai hoi
vu nang » vuc nang, va nang, vu dang
hieu va » lieu va, hieu qua
va cam » va cham, va cac, va cao
ma hoi » xa hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach vu nang ((ma hoi) OR (mai hoi)). hieu va cam duc ban hanh ((ki su) or (ky su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang ((ma hoi) OR (mai hoi)). hieu va cam duc ban hanh ((ki su) OR (ky su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach vu nang ((ma hoi) OR (mai hoi)). hieu va cam duc ban hanh ((ki su) or (ky su)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang ((ma hoi) OR (mai hoi)). hieu va cam duc ban hanh ((ki su) or (ky su)) triet*.