Perhaps you should try some spelling variations:
hanh via » hanh vi, hanh va, anh va
su sach » so sach, vu sach
via cua » gia cua, gian cua, giau cua
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach ty
hieu va » hieu qua
cua tre » cua te, cuu tre, cua triet
ky sang » ky nang, ky dang, ky tang
bao bo » bac bo, ban bo, nao bo
ma hoi » mai hoi, ma hoa, me hoi
bo va » bao va, do va, so va

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 ((ma hoi) or (xa hoi)). ((hieu va) OR (lieu va)) bao bo va hanh via cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ((ma hoi) OR (xa hoi)). ((hieu va) OR (lieu va)) bao bo va hanh via cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang ((ma hoi) or (xa hoi)). ((hieu va) OR (lieu va)) bao bo va hanh via cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ((ma hoi) or (xa hoi)). ((hieu va) OR (lieu va)) bao bo va hanh via cua tre*.