Perhaps you should try some spelling variations:
qua chat » qua nhat, qua cham, luan chat
van hanh » van thanh, ban hanh, van anh
chat xuc » chat huu, cam xuc, chao xu
va danh » va dinh, va dan, va hanh
cua tre » cua te, cuu tre, cua triet
ky tang » ky nang, ky dang, kho tang
cai ky » cao ky, cac ky, cam ky
ma hoi » mai hoi, xa hoi, me hoi
ca cua » co cua
tu cai » tu cac, tu can, tu bai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cai ky tang ((ma hoi) OR (ma hoa)). hieu qua chat xuc ((va danh) or (van hanh)) ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cai ky tang ((ma hoi) OR (ma hoa)). hieu qua chat xuc ((va danh) OR (van hanh)) ca cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cai ky tang ((ma hoi) OR (ma hoa)). hieu qua chat xuc ((va danh) or (van hanh)) ca cua tre".
• Adding a wildcard symbol may retrieve word variants: tu cai ky tang ((ma hoi) OR (ma hoa)). hieu qua chat xuc ((va danh) or (van hanh)) ca cua tre*.