Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
va hanh » van hanh, va thanh, va danh
sach ty » sach y, sach tu, sach thu
su sach » so sach, vu sach
ty hang » ly hang, ty xang, thi hang
va cam » va cham, va cao, va cai
xuc va » duc va, tuc va, luc va
vi cua » vai cua, di cua
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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 ty hang ((x hoi) OR (o hoi)). hieu ((va cam) or (va cac)) xuc va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty hang ((x hoi) OR (o hoi)). hieu ((va cam) OR (va cac)) xuc va hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty hang ((x hoi) OR (o hoi)). hieu ((va cam) or (va cac)) xuc va hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach ty hang ((x hoi) OR (o hoi)). hieu ((va cam) or (va cac)) xuc va hanh vi cua viet*.