Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cham xuc » cam xuc, chat xuc, cham soc
cao hoc » co hoc, cho hoc, chat hoc
hieu vu » hieu va, hieu su, dieu vu
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
dau cua » dai cua, day cua, cau cua
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau

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 cao hoc. ((hieu vu) OR (hieu ve)) cham xuc ((va hanh) or (va dan)) dau cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky nang cao hoc. ((hieu vu) OR (hieu ve)) cham xuc ((va hanh) OR (va dan)) dau cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky nang cao hoc. ((hieu vu) OR (hieu ve)) cham xuc ((va hanh) or (va dan)) dau cua tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky nang cao hoc. ((hieu vu) OR (hieu ve)) cham xuc ((va hanh) or (va dan)) dau cua tre*.