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How to Search in Biomedical Databases

Tutorials for Library Databases and Resources

Sample Search Step #6: Combining PICO Elements Using Boolean Operators

  • Recap: Each concept (Atorvastatin, Memory Loss, and Females) has been searched individually using keywords and MeSH terms. The creation of these three individual search strings will now allow you to combine them into a single search and locate any relevant publications that are highly specific to your topic.

  • After searching for all of your concepts individually, go to the “Advanced Search” page to combine all of them into a single search. The Advanced Search page can be reached by clicking on the following link located directly beneath the search box:

Screen-capture showing where to click in order to reach the advanced search page
  • On the page that opens (pictured below), you should see a listing of your search history with details on the number of results (as indicated by the arrows)

Screencapture showing advanced search page in PubMEd with the history and search details highlighted
  • The next step is to combine all three of this concepts into a single search string so that we locate results discussing all three concepts. As a refresher, please consider the following Boolean Operator visual for AND. We will use AND to combine these three search strings because we want results that discuss females AND memory loss AND Atorvastatin.
Graphic visualizing combining Searches w Boolean AND Graphic. Caption: "Using AND, this search would only retrieve results with disease and heart. "
  • To combine all three search strings within this advanced search page in PubMed, begin by clicking on the ". . ." option for the female search string in the column labeled "Actions." In the menu that opens after clicking on ". . .", select the first option labelled "Add query." Clicking this should cause the search string to populate the "Query box" towards the top of the screen. Here's a screen-capture showing where to click:
Screen-capture showing where to click in order to add the female search string to the query box within the advanced search page
  • After adding the first concept, add the second and third concepts by clicking on their ". . ." links under the column labeled "Actions." In the menu that opens, note that the options are different--it will prompt with multiple options to add the search. You will want to select the first option, "Add with AND," for both concepts (the strings for memory disorders and Atorvastatin), as pictured here:
Screen-capture showing how to add the second and third concepts to the query builder within the advanced search page
  • Selecting this option for the second and third concepts should cause them to populate the query box after the search string for female, separated by the Boolean operator AND. It should appear exactly like this:
Screen-capture showing the complete search string in the advanced search box with all three concepts separated by AND
  • The following search string is the exact same as what is captured in the screen-capture above. Note the use of parentheses surrounding the search string for each concept. These are automatically generated by the advanced search feature, and they are necessary to ensure that the search results include all three concepts together:

("​Female"[Mesh] OR Female*[tiab] OR Women[tiab] OR Woman[tiab])


("​Memory Disorders"[Mesh] OR "Memory Loss"[tiab] OR "Memory Disorder"[tiab] OR "Memory Disorders"[tiab] OR "Cognitive Retention Disorder"[tiab] OR "Cognitive Retention Disorders"[tiab] OR "Semantic Memory Disorder"[tiab] OR "Age Related Memory Disorder"[tiab] OR "Age Related Memory Disorders"[tiab] OR "Memory Deficit"[tiabOR "Memory Deficits"[tiab])


("​Atorvastatin"[Mesh] OR Atorvastatin[tiab] OR "(3R,5R)-7-(2-(4-Fluorophenyl)-5-isopropyl-3-phenyl-4-(phenylcarbamoyl)-1H-pyrrol-1-yl)-3,5-dihydroxyheptanoic acid"[tiab] OR "Atorvastatin Calcium"[tiab] OR "Atorvastatin, Calcium Salt"[tiab] OR Liptonorm[tiab] OR Lipitor[tiab] OR "Atorvastatin Calcium Hydrate"[tiab] OR "Atorvastatin Calcium Anhydrous"[tiab] OR "CI 981"[tiabOR "CI-981"[tiab] OR "CI981"[tiab] OR "Atorvastatin Calcium Trihydrate"[tiab])

  • Once all three concepts are in the query box as pictured above, click "Search" (pictured below)
Screen-capture showing how to complete search by click the search button
  • Upon clicking search, a set of results should open, as seen here:
Screen-capture of result list without limits applied