I did not get the full string from a serial port, some character was missing when I was reading from the serial port.
With so little to go on all that I can do is recommend that you read Robin2's serial input basics tutorial. If you want better help, you will need to ask a better question.
And, please read the "how to use the forum-please read" stickies to see how to ask a good question and how to post your code.
The how to ask a programming question thread has more information on what we need to know to be able to help you.