Issue while searching documents

Hello,
I have application, where we are uploading files of about 10 MB size;
The file contents are saved in the source of the index

The elasticsearch works fine, but i am facing memory issue while trying to search documents.
Elastic search loads the source for all the searched documents because of which i am facing memory issues.

What can be done reduce/improve memory usage while searching documents, or is there any way by which we can disable the source while searching and get the source only when required.

Thanks in Advance.