Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
sach ky » sach y, sach ty, sach kem
hieu va » lieu va, hieu qua
cam thu » nam thu, cac thu, ca thu
thu van » thuc van, thuy van, tu van
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
co hoi » co hoc, co loi
va cam » va cham, va cac, va cao
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: te ((sach ky) or (sac ky)) nang ((xa hoi) or (co hoi)). hieu va cam thu van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sac ky)) nang ((xa hoi) OR (co hoi)). hieu va cam thu van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) or (sac ky)) nang ((xa hoi) or (co hoi)). hieu va cam thu van hanh vi cua tre*.