Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, va tinh, le thanh
sach ky » sach y, sach ty, sach kem
nam xuc » cam xuc, nam xua, nam thuc
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
va cua » va chua, via cua, ca cua
x hoi » xa hoi, o hoi, x ho

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: su ((sach ky) OR (sac ky)) nang x hoi. hieu van nam xuc ((va thanh) OR (ban thanh)) va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sac ky)) nang x hoi. hieu van nam xuc ((va thanh) OR (ban thanh)) va cua tre~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sac ky)) nang x hoi. hieu van nam xuc ((va thanh) OR (ban thanh)) va cua tre*.