Hi Ashokharnal ,
In Alfresco when any property is defined using Content Model , you can also decide whether you want to maintain indexes for the property value.
Indexes has four parameters out of which one is tokenized . see the code snippet below
<property name="custom:name">
<title>Name</title>
<type>d:text</type>
<index enabled="true">
<atomic>true</atomic>
<stored>false</stored>
<tokenised>false</tokenised>
</index>
</property>
In your case if you make tokenised as false , you should be able to search complete string.
Thanks,