Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
pham duy » pham duc
ban hanh » ban hang
ky dang » ky danh
hieu va » lieu va
duy ban » uy ban, duy van, duy can
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((ky dang) OR (ky nang)) xa hoi. ((hieu va) OR (hieu qua)) pham duy ban hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((ky dang) or (ky nang)) xa hoi. ((hieu va) OR (hieu qua)) pham duy ban hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((ky dang) or (ky nang)) xa hoi. ((hieu va) OR (hieu qua)) pham duy ban hanh vi cua tre*.