Oxford Handbooks Online provides introductions and a critical survey of the current state of scholarship on major topics. The handbooks date from 2004 to present. Search by the name of the religion or concept.
The Cambridge Companions are great introductions to various religions. Search for the name of the religion you want to explore. Access to hundreds of electronic books, introductions to the major works and figures in the areas of literature, philosophy, religion and the classics.
Providing a comprehensive overview of one of Asia's most important religious and social forces, the "Encyclopedia of Buddhism describes the Buddhist world view, basic teachings and practices of Buddhism, as well as its different schools and sects. In addition to containing entries on Buddhist scriptures, art, architecture, saints, demons, monastic orders, festivals, rites and ceremonies, this new two-volume set explores the history of Buddhism, the different forms it has taken in different parts of the world, and how Buddhism has blended with other religions like Shinto, Confucianism, Taoism and Christianity.
The first edition of this reference work, called the Catholic Encyclopedia, was published around the turn of the 20th century, with the last revised edition appearing in 1967. This new edition includes the best of the previous entries - many completely revised and updated - as well as new entries, written by subject experts, covering the latest topics of interest. Many thousands of articles are biographical profiles of the people who make up the history of the Catholic Church.
Published by Brill, this is the authoritative encyclopedia on all aspects of the Islamic world. This database includes the complete 12 volume 2nd Edition, and the ongoing, completely new 3rd Edition, which has more entries on contemporary issues and current issues.
Encyclopedia of Indian Philosophies
This text is cataloged individually by volume. I suggest searching the title in the Library Search, "Encyclopedia of Indian Philosophies."