Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
cac tuc » cac toc, cac tac, cac nuoc
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
so sanh » do sanh
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, van nang
cac tu » cac thu, cach tu, cac du
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sanh)) v nang xa hoi. hieu van ((cac tuc) OR (cac tu)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sanh)) v nang xa hoi. hieu van ((cac tuc) OR (cac tu)) va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sanh)) v nang xa hoi. hieu van ((cac tuc) OR (cac tu)) va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sanh)) v nang xa hoi. hieu van ((cac tuc) OR (cac tu)) va hanh vi cua tre*.