Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu va » hieu qua
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
sach v » sach va, sach y, sach 2
v sang » va sang, ve sang, _ sang
ma hoi » mai hoi, ma hoa, me hoi
xuc va » duc va, tuc va, luc va
di va » dai va, di vao, doi va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach v sang ((ma hoi) OR (xa hoi)). ((hieu va) or (lieu va)) cam xuc va hanh di va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v sang ((ma hoi) OR (xa hoi)). ((hieu va) OR (lieu va)) cam xuc va hanh di va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach v sang ((ma hoi) OR (xa hoi)). ((hieu va) or (lieu va)) cam xuc va hanh di va thiet".
• Adding a wildcard symbol may retrieve word variants: toc sach v sang ((ma hoi) OR (xa hoi)). ((hieu va) or (lieu va)) cam xuc va hanh di va thiet*.