Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
va danh » va dinh, va hanh, dia danh
van cau » van dau, van hau, van chat
cau luc » cau truc, cau phuc
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
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: so sach ((ky lang) OR (ky tang)) xa hoi. hieu van cau luc ((va danh) OR (va dan)) vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ky lang) OR (ky tang)) xa hoi. hieu van cau luc ((va danh) or (va dan)) vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: so sach ((ky lang) OR (ky tang)) xa hoi. hieu van cau luc ((va danh) or (va dan)) vi cua tre*.