Enter Boolean operators ( AND, OR, NOT) in uppercase characters to combine search terms or phrases.
Click the green plus sign to add a new field of the same type. Boolean operators can be changed at left.
Click the Add New Field link to add a new field of a different type. Boolean operators can be changed at right.
Order of Precedence: Boolean operators on the left are executed BEFORE operators on the right.
For more complex searching of multiple concepts, click the blue Add New Search Group button to add a new search group to be combined with your initial search group.
For accurate results searching multi-word terms, place within quotation marks. The search engine will automatically insert an AND between multi-word terms without quotes. (Ex: "Barrier method*" OR "health care" OR "South Sudan" )