The National Diet Library provides the "Japanese Periodicals Index" as a search means for Japanese periodical articles from 1949. On November 4, the number of records exceeded 10 million.
The "Japanese Periodicals Index" indexes about 10,000 periodicals (so far accumulated about 20,000 periodicals). Its scopes in the field of periodicals and the volume of its records make it one of the leading databases of periodical articles in Japan.
Not only in the services of the National Diet Library (ex. the NDL-OPAC), this database is widely used in, for example, the CiNii of the National Institute of Informatics.