The new version of SharePoint offers more capabilities in the keyword syntax to enhance the search experience. While in the previous version you had to resort to FullText SQL queries, a lot of things can now be accomplished with keyword syntax.

For instance if you would like to filter on a date, you could use the following query:

LastModifiedTime>=01/06/2010

The actual format of the date depends on your regional settings (I’m using Dutch (nl-NL) in this case).

To search within a range of dates you can use the following query syntax:

LastModifiedTime:28/06/2010..30/06/2010

To exclude items you could use the following syntax:

LastModifiedTime<>28/06/2010

More info from MSDN about keyword syntax kan be found here: http://msdn.microsoft.com/en-us/library/ee558911.aspx