Perhaps you should try some spelling variations:
hanh than » hanh han, hanh nhan, hanh phan
than cua » nhan cua, thai cua, ban cua
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cuu tre, cua triet
cao duc » dao duc, cao suc, giao duc
cam duc » cam xuc, pham duc, nam duoc
nang xa » nang x, lang xa, nang ma
dai ky » dan ky, dai ly
sai ky » sac 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) OR (sai ky)) nang xa hoi. hieu qua ((cam duc) or (cao duc)) van hanh than cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((dai ky) OR (sai ky)) nang xa hoi. hieu qua ((cam duc) OR (cao duc)) van hanh than cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((dai ky) OR (sai ky)) nang xa hoi. hieu qua ((cam duc) or (cao duc)) van hanh than cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((dai ky) OR (sai ky)) nang xa hoi. hieu qua ((cam duc) or (cao duc)) van hanh than cua tre*.