This article shows how to easily set Google Search results restrictions.
In the top right corner of a Google Search page, click the bolt icon (tools) and click “Search Settings”.
You will then be prompted with a screen (as seen below) that allows you to choose if you want “no filtering” which includes all the dirties, or “Moderate”, which still seems to include the dirty stuff. or choose “Strict” which definitely shows only clean content.
Scroll down and click “Save”. Now your search results should look different.