Upper case is for names and cities. Lower case will give you more results Do not expect to find what you want the first try. Searching is a multi-step process. Learn the difference between subject and keyword searching. Use Boolean Logic to search.
Boolean logic is a way to a tell a computer how words or data sets relate to each other.
By using Boolean logic you can broaden or narrow your search to include more ideas than can be expressed by a single word or subject heading. Logical operators, words such as AND, OR, and NOT, have specific meaning in boolean logic. The AND operator tells the system that both words must be present in the search results. Use it to combine two ideas which must be present. The OR operator tells the system that either word should be present in the search results.