User-agent: Googlebot
Disallow: /*.pdf$
Disallow: /*.txt$
Disallow: /*.jpg$
Disallow: /*.gif$
Disallow: /*.png$
Disallow: /*.doc$

User-agent: *
Disallow: /*.pdf$
Disallow: /*.txt$
Disallow: /*.jpg$
Disallow: /*.gif$
Disallow: /*.png$
Disallow: /*.doc$