Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
hanh di » hanh vi, hanh de, hang di
hieu va » lieu va, hieu qua
dang xa » dang xay, lang xa, dang ha
san ky » sang ky, van ky, ban ky
va dau » va dao
dan ky » van ky
luc va » tuc va, loc va
di dau » doi dau, bi dau, di du

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((san ky) or (dan ky)) dang xa hoi. hieu va dau ((luc va) or (duc va)) hanh di dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((san ky) OR (dan ky)) dang xa hoi. hieu va dau ((luc va) OR (duc va)) hanh di dau tren.
• Adding a wildcard symbol may retrieve word variants: tu ((san ky) or (dan ky)) dang xa hoi. hieu va dau ((luc va) or (duc va)) hanh di dau tren*.