Tnx dear Masood, I got it.

Here's how to import your whole library with full texts into your new library:

1) Open the new library (the one you want your old library to go into)

2) Go to File > Import > File > Click Choose, then find where you saved the library you want to add to your new library and select it (make sure to click on the .enl file)

3) Change Import Option to EndNote library using the drop down arrow

4) Then click Import

- See also the attached image showing this process

I suggest you to use .enlx format to export your endnote file

so while you import it, all of your attachments will transfer immediately.