Perhaps you should try some spelling variations:
su sach » so sach, vu sach
cao hoi » cau hoi, cao hoc, tao hoi
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
y nang » ky nang, ly nang, v nang
co hoi » co hoc, co loi
va bao » va bai
bao bo » bac bo, ban bo, nao bo
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 y nang ((cao hoi) OR (co hoi)). lieu va bao bo va hanh va ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ((cao hoi) OR (co hoi)). lieu va bao bo va hanh va ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ((cao hoi) OR (co hoi)). lieu va bao bo va hanh va ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach y nang ((cao hoi) OR (co hoi)). lieu va bao bo va hanh va ((cua tre) or (cuu tre))*.