Library databases typically search a set of published works, but that doesn't mean those are always the types of publications you want, need, or are allowed to use. You can use the Source Type limiters to tell the database that you only want items from certain types of sources.
In the same way that IMDB.com tells you about a movie but doesn't give you access to the movie itself, the databases might have information to tell you about an item but not access to the item itself. You can tell the database that you only want items that you can access the item itself from that database by clicking on the "full text" limiter.
In some disciplines and for some topics it is important to use current information. You can tell the database to only give you results from a certain time period by limiting to a publication date range.
The subject limiter area is where you will find what tags are associated with the articles in your search results. Because these tags designate an article as being about that topic (rather than just mentioning the word) you can use these tags to tell the database that you only want articles tagged as being about that topic.
The default searches for your words within the same element using the word "and". This means that both words must be present. So if you were looking for a pizza with pepperoni AND mushrooms, you would not want one with only pepperoni or only mushrooms. Both ingredients must be on the pizza.
The word "or" is used to tell the database that as long as one or the other of your words show up, you would like to see it. If you wanted pizza with pepperoni OR mushrooms, you would be given all the options that have either pepperoni or mushrooms, including those that have both pepperoni and mushrooms.
You can use the word NOT to tell the database that you want certain things but not other things. If you would be happy with pepperoni OR mushrooms on your pizza but olives gross you out, you can tell the database not to include them with NOT.
