Perhaps you should try some spelling variations:
hanh dai » hanh tai, hanh dao, vanh dai
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
doc hoi » duoc hoi, hoc hoi, doi hoi
va hanh » van hanh, va thanh, va danh
doc hai » hoc hai, duc hai, ngoc hai
cam luc » cam xuc, cau luc
luc va » duc va, tuc va, loc va
ve cam » ve cham, ve cac, va cam
tu can » tu ban, tu cac, thu canh
can ky » van ky, dan ky, ban ky
do hai » do thai, do dai, co hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu can ky nang ((doc hoi) or (((doc hai) OR (do hai)))). hieu ve cam luc va hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu can ky nang ((doc hoi) OR (((doc hai) OR (do hai)))). hieu ve cam luc va hanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu can ky nang ((doc hoi) or (((doc hai) OR (do hai)))). hieu ve cam luc va hanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu can ky nang ((doc hoi) or (((doc hai) OR (do hai)))). hieu ve cam luc va hanh dai cua tre*.