Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh hai » thanh hai, nhanh hai, hang hai
te sach » toc sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu van
hieu va » lieu va, hieu qua
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
cac bo » bac bo, cac co
bo van » vo van, so van, do van

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 nang xa hoi. ((hieu ve) or (hieu va)) cac bo van hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang xa hoi. ((hieu ve) OR (hieu va)) cac bo van hanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ky nang xa hoi. ((hieu ve) or (hieu va)) cac bo van hanh hai cua tre*.