UCL Explore is UCL's search tool which allows you to search across a wide range of resources. This page includes some advice on how to use Explore effectively.
This video (3'44") will give you an overview of what you can find using Explore, as well as basic instructions on how to carry out a search.
Remember if you are combining words in Explore using Boolean operators (AND, OR, NOT) you must enter them in upper case, e.g. doctor OR physician