Perhaps you should try some spelling variations:
thanh thai » thanh hai, thanh tai, nhanh thai
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
thai cua » than cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, pham duc
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
su dai » sau dai, si dai, su tai
su sai » su tai, su hai, su mai

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) OR (su dai)) ky lang xa hoi. hieu van ((cam duc) or (giao duc)) van thanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sai) OR (su dai)) ky lang xa hoi. hieu van ((cam duc) OR (giao duc)) van thanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sai) OR (su dai)) ky lang xa hoi. hieu van ((cam duc) or (giao duc)) van thanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sai) OR (su dai)) ky lang xa hoi. hieu van ((cam duc) or (giao duc)) van thanh thai cua tre*.