Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
hieu ve » hieu va, hieu van
cam duc » cam xuc, pham duc, nam duoc
cao duc » dao duc, cao suc, giao duc
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cac ky ((nang x) or (mang may)) hoi. hieu ve ((cam duc) OR (cao duc)) van hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky ((nang x) OR (mang may)) hoi. hieu ve ((cam duc) OR (cao duc)) van hanh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky ((nang x) or (mang may)) hoi. hieu ve ((cam duc) OR (cao duc)) van hanh tai cua tre*".