Perhaps you should try some spelling variations:
so sach » so sanh, bo sach, co sach
ty tang » tay tang, ty hang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
hieu vu » hieu va, hieu ve, hieu su
vu pham » su pham, vi pham, vu kham
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ((ty tang) or (ty xang)) mai hoi. hieu vu pham duc va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ty tang) OR (ty xang)) mai hoi. hieu vu pham duc va hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach ((ty tang) or (ty xang)) mai hoi. hieu vu pham duc va hanh va cua tre*.