Scope

• Combining sets of results enables you to increase the precision of your search.

Requirements and Limitations

• You can use Boolean operators to combine two or more sets of results by using the R# numbers to the left of the set.
• You can also use nesting with parentheses ( ).
• You can not combine the sets through the use of proximity operators.

Example

• A search on anthrax or smallpox give me the first set:
  • R1 (Anthrax or smallpox)
  • View 1014 Citations; Modify Search
• A search on terrorism give me the second set:
  • R2 (Terrorism)
  • View 565 Citations; Modify Search
• A search on "public health" give me the third set:
  • R3 ("Public health")
  • View 13246 Citations; Modify Search
• I combine the sets as follows: r3 and (r2 or r1) to get the fourth set:
  • R4 (R3 and (R2 or r1))
  • View 138 Citations; Modify Search