Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
dung cong » dung trong
hieu ven » hieu van, hieu ve, hieu tren
dung co » dung cho, dung cua
cua tre » cua te, cuu tre, cua triet
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
sac ky » cac ky, sai ky
dam tu » nam tu, cam tu, tam tu
tu vat » tu va, tu van, tu bat
so sac » so sach, so dac

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sac ky dang xa hoi. ((hieu ven) or (hieu hien)) dam tu vat ((dung co) OR (dung cong)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sac ky dang xa hoi. ((hieu ven) OR (hieu hien)) dam tu vat ((dung co) OR (dung cong)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sac ky dang xa hoi. ((hieu ven) or (hieu hien)) dam tu vat ((dung co) OR (dung cong)) cua tre*".