Perhaps you should try some spelling variations:
van vanh » van anh, van hanh, van manh
vanh tai » van tai, hanh tai, anh tai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cso hai » co hai, cho hai, cao khai
hieu ve » hieu va, hieu van
cac vuc » cac nuoc, cac vung, cac cuoc
vuc van » duc van, luc van, thuc van
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
so hai » son hai, su hai, so ha
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ((so hai) or (cso hai)). hieu ve cac vuc van vanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((so hai) OR (cso hai)). hieu ve cac vuc van vanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((so hai) or (cso hai)). hieu ve cac vuc van vanh tai cua tre*.