Choosing a topic - where do you begin?
Many students choose a topic that they already know something about and explore new research in that area. Whatever you choose, make sure you are interested in the topic!
Too big or too little?
A quick way to get a feel for how well your area has been researched is to run a search in Google Scholar. If only 10 hits are returned you'll know you have to expand your topic or change your topic. There just isn't enough information. On the other hand, if you get 10,000 hits you'll know you have to narrow down your topic. Google Scholar also has a date filter on the left navigation bar to limit results by date.
When you search Google Scholar, the scientific articles in the databases listed below may be included in your results. Scholar acts as an umbrella search engine for all of them and displays information when the library has access to the journal.
However, searching each database individually will give you a better hit rate because of the specialized search "bells and whistles" of the individual database.
If you find that most of the hits you find useful come from a particular database, go to that database to run your search. You'll weed out the citations that don't relate to your topic.