Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
duc van » duc va, duc tan, duc manh
cuc tre » duc tre, cua tre, cuu tre
su dai » sau dai, si dai, su tai
dai ky » dan ky, dai ly, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su dai ky dang xa hoi. ((hieu ve) or (hieu qua)) cam duc van hanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su dai ky dang xa hoi. ((hieu ve) OR (hieu qua)) cam duc van hanh tai cuc tre.
• Adding a wildcard symbol may retrieve word variants: su dai ky dang xa hoi. ((hieu ve) or (hieu qua)) cam duc van hanh tai cuc tre*.