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