I can't go to iTunes Store with my iPod Touch

Hello,

I have a problem with using iTunes with my iPod touch. I tap "iTunes" button in my iPod, and there are just audiobooks and podcasts to download. When I search for something via "Search" buttons, iPod searches just in audiobooks and podcasts. I have iTunes account, but still don't know what do. Help me, tell me how to open full iTunes store on my iPod.
Thanks for your help, sorry for bad English :)