Perhaps you should try some spelling variations:
thanh vinh » thanh tinh, than kinh, thanh van
thanh binh » thai binh, than kinh, tinh binh
hieu van » hieu va, thien van, lieu va
nang xa » nang x, lang xa, nang ma
cac duc » cac du, cao duc, cac nuoc
cac dac » cac dan, cac dai, cac bac
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 xa hoi. hieu van ((cac duc) OR (cac dac)) van ((thanh vinh) or (thanh binh)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky nang xa hoi. hieu van ((cac duc) OR (cac dac)) van ((thanh vinh) OR (thanh binh)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky nang xa hoi. hieu van ((cac duc) OR (cac dac)) van ((thanh vinh) or (thanh binh)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu cac ky nang xa hoi. hieu van ((cac duc) OR (cac dac)) van ((thanh vinh) or (thanh binh)) cua tre*.