In ubuntu 14.04, if you're using your Dash to search something by default it will also search for the online resources related to your keywords. That's pretty annoying and will slow down the search. I believe that most of us prefer local search instead of dual search (local + online).
To stop this is a very easy job. Goto your system Setting
Choose Security & Privacy and then Click tab 'search', you'll see smth like the following picture
Spot that switch (on/off) button ? just turn it OFF you're done !.