1, printing type: it is the most basic way of literature, including lead printing, mimeograph, offset printing, lithograph and other materials. Advantages: you can read directly, which is convenient and fast.
2. Microfilm: A document based on photosensitive materials, which can be divided into microfilm and microfilm. Its advantages are small size and convenient storage, transfer and transportation. But you must use a reader when reading.
3. Computer readable: It is the latest form of carrier. Mainly through coding and programming, files are converted into symbols and machine language, input into computers, stored on magnetic tapes or disks, and then output by computers when reading. It can store a large amount of information, organize it in any form, and extract the required information from it at a very fast speed. The emergence of e-books belongs to this type.
4. Audio-visual type: also known as direct-view type or audio-visual type, it is a file recorded on the carrier in the form of sound and image, such as records, audio tapes, video tapes, science and technology movies, slides, etc.
Impact factor (IF)
According to the statistics of China HowNet on April 4th, 2020, this document was downloaded 9 times14238 times and cited 13474 times. The comprehensive impact factor of (version 20 19) is 0.22 1 and that of (version 20 19) is 0.66.
According to the statistics of Wanfang Data Knowledge Service Platform on April 4, 2020, this document was cited 4908 times and downloaded 32640 times. According to the statistics of Citation Report of China Journals (Extended Edition) in 20 17, the impact factor of this journal is 0. 16, ranking 6066th among all statistical source journals (6670 kinds).