Database of interacting proteins (DIP) - http://dip.doe-mbi.ucla.edu/

Declassified documents reference system - 
http://gale.cengage.com/customer_service/sample_searches/ddrs.htm

Dendrome - http://dendrome.ucdavis.edu/  

Descriptions of plant viruses - http://www.dpvweb.net/ 

Design And Applied Arts Index - 
http://www.csa.com/factsheets/daai-set-c.php 

Dictionary of commonly cited compounds - 
http://www.chemnetbase.com/scripts/dcccweb.exe?welcome-main 

Dictionary of inorganic and organometallic compounds - 
http://www.chemnetbase.com/tours/dioc/index.html

Digital National Security Archive - http://www.gwu.edu/~nsarchiv/

DIPPR chemical database – http://www.knovel.com/

Dissertations & theses - http://www.ndltd.org/browse

DOE information bridge - http://www.osti.gov/bridge/