Medical Image Database at NLM

Instruction:

The available Boolean operators are:

  • AND - only those citations that contain selected terms.
  • OR - citations that contain at least one of the selected terms.
  • NOT - exclude citations with the selected term.

    Boolean and Syntax

    - If Boolean operators are not entered, NLM Image Database assumes it is one long term.
    - NLM Image Database processes all Boolean connectors in a left-to-right sequence. You can change the order that the Database processes a search statement by enclosing concepts in parentheses. The terms inside the set of parentheses will be processed as a unit and then incorporated into the overall strategy.
    Example: bone marrow AND (Reed-Sternberg OR lymphocyte)