Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ve ban » te ban, va ban, ve bao
vi cua » vai cua, di cua
ve bac » ve bao, ve cac, he bac
x hoi » xa hoi, o hoi, x ho
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: ((tu sach) OR (thu sach)) ky nang x hoi. hieu ((ve bac) or (ve ban)) bo va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang x hoi. hieu ((ve bac) OR (ve ban)) bo va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky nang x hoi. hieu ((ve bac) or (ve ban)) bo va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky nang x hoi. hieu ((ve bac) or (ve ban)) bo va hanh vi cua tre*.