These sources provide full text entries online:

• Encyclopedia Britannica Online 
   
• Blackwell Reference Online
   
• CQ Researcher 
   
• Gale Virtual Reference Library (GVRL)​
  

Theology/Religion:

• Encyclopedia of Religion.
• New Catholic Encyclopedia.
• Encyclopedia Judaica.
• Encyclopedia of Islam.

Literature:

• Literature Resource Center.
• MagillOnLiterature.
• Johns Hopkins Guide to Literary Theory and Criticism.

Science:

• CRC Handbook of Chemistry and Physics 
• McGraw-Hill Concise Encyclopedia of Science and Technololgy

History:

• Cambridge Histories Online 
• International Encyclopaedia for the Middle Ages
• Encyclopedia of Africa 

Psychology:

• The Corsini Encyclopedia of Psychology and Behaviorial Science (3rd ed.)
• The Gale Encyclopedia of Psychology (2nd ed.)

Social Sciences:

• International Encyclopedia of the Social Sciences.
• Human Relations Area Files -  World Cultures.

Sociology:

• Blackwell Encyclopedia of Sociology 

Arts:

• Oxford Music Online.
• Oxford Art Online.

For more encyclopedias, go to Librarian Subject Pages