Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
cac toc » cac toi, cac nuoc, cac thoi
sach ky » sac ky, sach ty, sach kem
cac tuc » cac tu, cac tac, cac nuoc
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca 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: su ((sach ky) OR (sach y)) nang xa hoi. hieu van ((cac tuc) OR (cac toc)) va hanh va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach y)) nang xa hoi. hieu van ((cac tuc) or (cac toc)) va hanh va cua tre~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sach y)) nang xa hoi. hieu van ((cac tuc) or (cac toc)) va hanh va cua tre*.