Perhaps you should try some spelling variations:
va hanh » van hanh, va thanh, va danh
va tinh » may tinh
cua tre » cua te, cuu tre, cua triet
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
ve cao » va cao, ve bao, ve co
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho

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 ky nang x hoi. hieu ((ve cao) OR (ve cac)) duc ((va hanh) or (va tinh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang x hoi. hieu ((ve cao) OR (ve cac)) duc ((va hanh) OR (va tinh)) dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang x hoi. hieu ((ve cao) OR (ve cac)) duc ((va hanh) or (va tinh)) dai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang x hoi. hieu ((ve cao) OR (ve cac)) duc ((va hanh) or (va tinh)) dai cua tre*.