Not sure if I got your request properly, but maybe like this:
Create an OnActivateSheet trigger for your sheet (Sheet properties -> Triggers), with an Selection - Select in field action.
Set your field you want to filter (I assume Year) in the Field entry box:
and as search expression:
So whenever you enter this sheet, 2012 is selected in your data.
If you would like a specific table or chart to only show values for one year (or one month, or any other selection), you can use Set Analysis. You would normally put these in your Expressions, e.g.
Dimension: Month, Item Type
You can use this expression in multiple charts, of course, and you don't have to make any selections for that chart to show 2012 values.
For writing out Set Analysis syntax, I recommend http://www.qlikblog.at/1384/set-analysis-wizard-qlikview/ - a handy wizard for generating set analysis statements.