You can't do it for all Google, but if you use Chrome, you can set it as the Omnibox default. Go to Menu -> Settings -> Search -> Manage Search Engines, then add a new row at the bottom that says "Google Verbatim", "verbatim", "https://www.google.com/search?tbs=li:1&q=%s", hit Done and click "Manage Search Engines" again, then find that row in the list above (alphabetical) and click "Make default". Now everything in the address bar uses verbatim search.
