User-agent: Yandex
Disallow: /
User-agent: Baiduspider
Disallow: /
User-agent: Googlebot
Disallow: /
User-agent: Slurp
Disallow: /

RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Baiduspider [NC]
RewriteRule .* – [F,L]