Using course tools>>Discussion Board>>Participating in forums
You can search through messages in a Discussion Board forum by author or one or more keywords.
Click Search on the far right above the messages.
Indicate what areas you want to search:
All searches the sender, subject, and body of each message.
Subject searches only the subject of each message.
Subject & Body searches the subject and the body of each message.
If you want to search only those messages sent by a particular person, select the person's name in the By Author box.
To search by one or more words, type the word or words in the Keywords box. Separate words with a comma.
Click Any to view messages that contain any keyword.
Click All of these to view only those messages that contain all the keywords.
To sort the results of the search based on author, date, or subject, select an option in the Sort by drop-down list.
Indicate how many messages to display at once and whether to expand them.
Select Expand Messages if you want to display each message body as well as the message subject.
Click Submit.