(1) printed literature. It is a scientific and technological document made by means of lithography, lead printing, offset printing, electrostatic copying and so on. Readers can read the literature directly, but because it is based on paper, it has low storage density, large space and large occupation space.

(2) Miniaturization of documents It is a scientific and technological document produced by using photosensitive materials as the carrier and microfilm as the recording means. Such as microfilm, microfiche, microfiche, etc. With the application of laser and holographic technology, ultra-microfilm has appeared. Its advantages are low cost, small size, convenient collection, long storage time and easy automatic management and retrieval. The disadvantage is that this type of literature must be read by micro-reader, and can not be directly consulted.

(3) machine-readable literature. Or computer-readable literature. It takes magnetic material as carrier and optical character recognition device as recording means. Through coding and programming, it turns scientific and technological documents into symbols that computers can recognize, and then outputs them. Its advantages are large storage capacity and quick retrieval of required files. But it can only be used with the help of a computer, and the use cost is high.

(4) Audio-visual literature. It uses magnetic materials or photosensitive materials as carriers and uses special mechanical devices to record information directly. It is a new document with pictures and texts, including slides, videos, sci-tech movies, records, tapes and so on. It is characterized by alternating movements, rich sounds and feelings, and vivid images. So it is also called audiovisual literature.