In February's search training I mentioned some keyword strings I use to help narrow down a set when an age limit isn't restrictive enough to get a set down to a manageable number of relevant articles. Remember that you'll need to search these as title/abstract words(.ti,ab. or .tw.), not a a general keyword search (.mp) because that will search the subject headings and defeat the purpose.
As with any keyword search strategy, you'll inevitably miss some things and pick up things that aren't relevant, but these are a pretty good way to narrow down a big set. A good keyword strategy strikes a happy balance between being inclusive and exclusive. It's one tool in your toolkit - as with any search, you should always try a few different approaches and don't blindly rely on just one method.
I pretty much just made up these keyword strings, so feel free to add comments if you think of additions or modifications! :)
As always, let me know if you have questions.
child$ or pediatric$ or paediatric$ or school$ or young$
adolescen$ or teen$ or young adult$ or school$
elder$ or geriatric$ or aged or old age or older