Why print() only print the same string once?

Here is my script:

for (int j = 0; j < 10; j++){
 print("hello world");//it just print once in a line,not 10 times   }

I know this script is a bit fool,but in some cases,I need to see the result even it print once or the same as before.

but neither print() or Debug.log() can't display it again.

How to fix it? Thx.