In the Advanced Word Search area, go to the Year item published boxes and type a year in the box after "After." The date you use is not inclusive. In other words, if you type 1994, your search will return results published after but not including 1994.
Leaving the "Before" box empty will return the most recent items. You may include a date if you'd like, but it is also not inclusive. You will find items up to but not including the date you type.