There are a number of ways to do this depending on the system you use (or at the very least the character sheet in use). Simplest would be to copy the stat block for a monster into it's bio/gm notes on the journal. Alternatively you could have them in handouts and create a master handout which links to all of the others so you can quickly call them up during play.
Personally i have the stats in the bio tab and then i can shift-click on a monsters token to bring up the sheet and the required information. If you want to get fancier you can use macros that whispers the information to yourself and set this as available in your macro bar so you can select a token, click the button and get the info in chat for your reference?
Again, all depends on the amount of information and whether or not you are always wanting to look at the same information each time, a basic example (with made up attribute names for ease) would be:
/w gm Hit Points = [[@{selected|hitpoints}]] / [[@{selected|hitpoints|max}]], Armour Class = [[@{selected|armourclass}]], Special abilities = [[@{selected|specialabilities}]]etc etc
More than happy to help if you can give an idea of the type of information and the character sheet being used, otherwise the wiki is certainly the place to go for a macro crash course :)
