Perhaps you should try some spelling variations:
tuan thai » xuan thai, tuan khai, than thoai
tuan tai » toan tai, quan tai, tan tai
cua tre » cua te, cuu tre, cua triet
cac luc » cau luc, coc luc, cac nuoc
hieu ve » hieu va, hieu van
luc van » luoc van, luu van, duc van
tu sac » tu sach, tu cac, tu bac
nang o » nang co, nang ho, nang ro
tu san » thu san, tu ban, tu can
ve cac » va cac, vien cac
o lai » o lao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sac) or (tu san)) ky nang o lai. hieu ve cac luc van ((tuan thai) OR (tuan tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sac) OR (tu san)) ky nang o lai. hieu ve cac luc van ((tuan thai) OR (tuan tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sac) or (tu san)) ky nang o lai. hieu ve cac luc van ((tuan thai) OR (tuan tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sac) or (tu san)) ky nang o lai. hieu ve cac luc van ((tuan thai) OR (tuan tai)) cua tre*.