Perhaps you should try some spelling variations:
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
dai hoi » dai hoc, dai hai, dai moi
lai hoi » lai hoa, lai roi, mai hoi
ky sang » ky nang, ky dang, ky tang
xuc va » duc va, tuc va, luc va
vi cua » vai cua, di cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky sang ((lai hoi) OR (dai hoi)). ((hieu ve) or (hieu va)) cam xuc va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ((lai hoi) OR (dai hoi)). ((hieu ve) OR (hieu va)) cam xuc va hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang ((lai hoi) OR (dai hoi)). ((hieu ve) or (hieu va)) cam xuc va hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ((lai hoi) OR (dai hoi)). ((hieu ve) or (hieu va)) cam xuc va hanh vi cua te*.