Hi Girija,
In future, please add the version to the post.
Use the percent symbol (%) in the Value field to represent a string of
characters. The percent symbol can also be included in a string. For example,
if you want to filter for any Microsoft application, you can enter
Microsoft%. Any string that begins with Microsoft is included in the view.
Use the underscore character (_) in the Value field to filter for a single
wildcard character in a string of characters. For example, if you want to
filter for a specific type of task (Training classes), you can enter Training
_ Class and the filter returns Training A Class, Training B Class, and so on.
You can get more information from
http://office.microsoft.com/en-us/projservadmin/HA011643151033.aspx