The Outlook add-in provides controls for this:
Open the Conversation you want to search.
Click Find messages in Conversation, which is the icon that looks like a magnifying glass.
In the Find drop-down, select Messages.
Enter the search term in the Text field.
Use the up and down arrows to step through the search results.
If you're using Oracle Social Network in your browser, it's still possible to search for individual keywords across all Conversations: