The huge size of these databases with millions of references, and abstracts from thousands of journals means that if the information you seek has been published, the references are there. The biggest problem with these databases tends to be getting too much information, not too little. Using Medical Databases Typically each reference will be indexed under a variety of terms. You search for references on a subject by asking for the references indexed under terms related to that subject. This will result in a list of all of these references which you can then peruse or download to your computer.
Databases vary as to what terms are indexed.
Often words such as the words in the title, or even words in the abstract are indexed. The problem with looking for literal words in the title is that there are usually lots of synonyms and variations for any word. Some databases allow you to type only the first part of the word, to give you all words that start with that part in common, or allow you to use wild card characters. This is helpful, but there is a better solution. The better databases, including MedLine, include a set of concept terms called MeSH terms.