Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
mai khoi » mai khoa, tai khoa, dai khoa
hanh tai » thanh tai, hang tai, han tai
cac khoi » cac thoi, cac khoan, cach thoi
cuu tre » cua tre, cau tren, cau treo
tai cuu » tai cuc, tai buu, tai cua
va hanh » van hanh, va thanh, va danh
xuc va » duc va, tuc va, luc va
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky
ve cac » va cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky nang ((mai khoi) or (cac khoi)). hieu ((ve cac) OR (vien cac)) xuc va hanh tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky nang ((mai khoi) OR (cac khoi)). hieu ((ve cac) OR (vien cac)) xuc va hanh tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky nang ((mai khoi) or (cac khoi)). hieu ((ve cac) OR (vien cac)) xuc va hanh tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sac ky nang ((mai khoi) or (cac khoi)). hieu ((ve cac) OR (vien cac)) xuc va hanh tai cuu tre*.