How to check the literature type

See the references: general books [M], journal articles [J], newspaper articles [N], papers [C], dissertations [D], reports [R], standards [s], patents [P], databases [DB], computer programs [CP], electronic bulletin [EB] and so on.

When searching in the literature database, there are literature types:

The following figure is the search paper page in HowNet.

The database of Science Network searches for information about foreign literature. For example, the following document types display recurring documents: