Perhaps you should try some spelling variations:
vu sach » vu bach, su sach, vu khach
sach ty » sach y, sach tu, sach thu
ty hang » ly hang, ty xang, thi hang
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ve cac » vien cac
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, 5 hoi

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

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