Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
vu khach » vu khanh, vu khac, vay khach
vu sach » vu bach, su sach
cam tuc » cam xuc, nam thuc, dam thuc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
cam tu » cam thu, nam tu, dam tu
vi cua » vai cua, di 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: ((vu sach) or (vu khach)) ky nang x hoi. hieu ve ((cam tuc) OR (cam tu)) van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (vu khach)) ky nang x hoi. hieu ve ((cam tuc) OR (cam tu)) van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) or (vu khach)) ky nang x hoi. hieu ve ((cam tuc) OR (cam tu)) van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) or (vu khach)) ky nang x hoi. hieu ve ((cam tuc) OR (cam tu)) van hanh vi cua tre*.