Delete text if screen is under 979px wide in bootstrap

Well I have a little problem; I have some text in my heading that looks like this (979px wide) http://ift.tt/1JnDwQK

And if the user screen is under 979px the text goes like this http://ift.tt/1cGeiAi

So I need to remove that text if the screen is under 979px

Thanks in advance, Carlos.

PD : I'm using bootstrap and the heading is built in php