Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dieu cua » dieu tra
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
cao luc » bao luc, cao duc, cao suc
cua tre » cua te, cuu tre, cua triet
va nang » van nang, da nang, cam nang
v nang » vu nang, van nang, voi nang
va cao » va cac, va co, va dao
x hoi » xa hoi, o hoi, x ho

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