Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » thien van, lieu va, hieu ve
van hanh » van thanh, ban hanh, van anh
hieu va » lieu va, hieu qua
xuc van » duc van, luc van, vuc van
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
x hoi » o hoi, x ho, 5 hoi

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