Minimize Menu Items?

Hello!

On my website, if the browser is not maximize it looks like this:
http://postimg.org/image/6381wc86p/

versus how it normally looks:
http://postimg.org/image/iu8heojav/

Is there anyway to make it so when the page is not fully maximized that a drop down menu or something appears on the left side with the items not being shown?

Thanks