When using several Boolean operators, you should always group to determine how the operators are to be applied. This field allows you to search the full text of the abstracts. When using several Boolean operators, you should always group to determine how the operators are to be applied. Document Publication Date used for searching for documents published within a specific date range or on a specific date.
Number is assigned by the issuing or processing organization.
Subject Categories are used to define broad subject areas in the field of energy.