Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
thuc day » thuc dan
sach ky » sac ky, sach y, sach ty
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang co » nang cao, nang doc, nang noi
co hoi » co hoc, co loi
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: hoc sach ky nang co hoi. ((hieu ve) or (hieu va)) nam ((thuc day) OR (thuc vat)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky nang co hoi. ((hieu ve) OR (hieu va)) nam ((thuc day) OR (thuc vat)) hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky nang co hoi. ((hieu ve) or (hieu va)) nam ((thuc day) OR (thuc vat)) hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky nang co hoi. ((hieu ve) or (hieu va)) nam ((thuc day) OR (thuc vat)) hanh va cua tre*.