Perhaps you should try some spelling variations:
vien cac » vien dai, vien da, gian cac
van hanh » van thanh, ban hanh, van anh
hanh tai » thanh tai, hang tai, han tai
duc van » duc va, duc tan, duc manh
tai cuu » tai cuc, tai buu, tai cua
cuu tre » cua tre, cau tren, cau treo
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
co loi » co hoi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang ((co loi) OR (co hoc)). hieu ((vien cac) OR (vien bach)) duc van hanh tai cuu tre~.
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang ((co loi) or (co hoc)). hieu ((vien cac) or (vien bach)) duc van hanh tai cuu tre*.