In most cases, a keyword search is the best way to search for books or articles on a topic.
To get the best results, think of the most important concepts in your search, then enter them in the search box.
For example, if you are researching a paper about how ADHD is diagnosed the search Attention Deficit Disorder Diagnosis or a phrase like Diagnosing Attention Deficit Disorder would both be effective searches.
Try experimenting with other terms to find more books or articles. For example, if you are researching Attention Deficit Disorder, try alternate words such as ADHD and Attention Deficit Hyperactivity Disorder in your search to get more or different hits. To better focus your search, add another term: for example Adult.