Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
so sanh » do sanh
hanh va » hang va, hanh vi
nam xuc » cam xuc, nam xua, nam duoc
te sach » toc sach
cua tre » cua te, cuu tre, cua triet
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.

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