If you are on a Legal plan you will have access to the Conflict Checker. Top right, click the check mark icon in your navigation bar.
The conflict checker will search through all Clients, Client Notes, Projects, Project Notes, Contacts, Time Entries, Expense Entries, Internal Time Entries, and Scheduled events.
To access to the Conflict Checker a user must have the permissions to "Create/edit clients", "Create/edit/close projects", and "View other users' time/expenses" enabled in their permissions.
Also asked as: Does Bill4Time have some kind of searchable narrative?