Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
van thanh » ban thanh, van tuan
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, nam duoc
hieu ve » hieu va, hieu van
ky tang » ky nang, ky dang, kho tang
sai ky » sac ky
ma hoi » mai hoi, ma hoa, me hoi
su sai » su tai, su hai, su dai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sai ky tang ((ma hoi) OR (xa hoi)). hieu ve ((cam duc) or (pham duc)) van thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sai ky tang ((ma hoi) OR (xa hoi)). hieu ve ((cam duc) OR (pham duc)) van thanh dai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sai ky tang ((ma hoi) OR (xa hoi)). hieu ve ((cam duc) or (pham duc)) van thanh dai cua tre*".