It is a powerful research tool to allow researchers to do keyword search across over 400 rare gazetteers and download the content in CVS files. A bunch of visualization tools are provided as well. You need to sign up for a free account to use it. Searches need to be done in traditional Chinese characters.
Funded by the Chiang Ching-Kuo Foundation for International Scholarly Exchange, the Institute of History and Philology and the National Institute of Korean History of Korea exchanged their collections of the Veritable Records of the Ming, the Veritable Records of the Qing and the Annals of the Joseon Dynasty and collaborated on the making of a full text digital archive of the three historical data.
It provides search in millions of archive documents from the Ming, Qing and Republican China periods. All metadata and text extracts are open-access. To access original images, researchers need to contact the individual database provider.