Abstract: The present disclosure relates to an organic electroluminescent device. The organic electroluminescent device of the present disclosure shows high luminous efficiency and good lifespan by comprising a specific combination of the plural kinds of host compounds and a specific hole transport compound.

Abstract: The present invention relates to a multi-component host material and an organic electroluminescent device comprising the same. By comprising a specific combination of the multi-component host compounds, the organic electroluminescent device according to the present invention can provide high luminous efficiency and excellent lifespan characteristics.

Abstract: The present disclosure relates to an organic electroluminescent device. The organic electroluminescent device of the present disclosure shows high luminous efficiency and good lifespan by comprising a specific combination of the plural kinds of host compounds and a specific hole transport compound.

Abstract: Provided is a method and apparatus for providing an indexing service in a portable terminal. The method includes recognizing at least one data selected by a user from a first file provided through a text viewer of the portable terminal and extracting absolute locations of the recognized data in the first file, storing the extracted locations of the data and arranging the data in a predetermined order to create a first sub file related to the first file, and indexing the first file to allow a search in the first file based on particular data by displaying the locations stored for the respective data arranged in the created first sub file. The first sub file is further linked to data from other files according to the data selected by a user so that a user can determine location of a particular data.

Abstract: A method and apparatus for deleting communication history wherein communication data is deleted while deleting a communication history in a portable terminal. When communication information about a particular phone number or a particular person name is intended to be deleted, the method can search and delete a communication history and communication data, where the communication history includes call history, missed call history, call rejection history, message history, etc.