All Curiosity systems support natural language time filtering directly in the search box. Add for example to your query terms like "since last month", or "from 2010 to 2012" in one of the configured languages and Curiosity will understand you and automatically filter your data to the time period you referred to.
Search after a certain time
Enter "since [date]" in the search bar to get all results after this date:
Search before a certain time
Enter "before [date]" in the search bar to get all documents of this topic from before this date:
Search within a specific time period
Enter "between [date] and [date]" in the search bar to get all documents of this topic from this time period:
If Curiosity recognized your search term as a time filter but you actually want to search for the text, you can click on the button shown when hovering over the search box: