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PubMed: The Basics: Beginning the Search

A how-to guide on using and searching the New PubMed

Beginning the Search

The first step in beginning your search is to develop a search strategy. Once you have a question or topic in mind, try to identify the major concepts and key ideas.

Keep in mind that PubMed is best for finding information for specific, focused questions and topics. Background or factual questions (i.e., how is diabetes treated?) are best answered through textbooks, point-of-care tools, and other similar reference resources. If you're unsure if your question is specific enough, you should have at least two or three concepts identified from your topic.

To learn more about planning your search, read the following sections:

Concept Tables

Concept tables can be a useful method for identifying main ideas.

The table below shows how for each concept we identify, there can be many synonyms, acronyms, and other like-phrases to be used as possible search terms. To construct a thorough search, it's important to think of all the possible ways someone might have expressed an idea in writing. Then it will be easier to choose which search terms to use in PubMed.

Are e-cigarettes an effective smoking cessation method for patients with COPD?
E-cigarettes Smoking Cessation COPD



electronic cigarette

electronic cigarettes



smoking cessation

quit smoking

quitting smoking

stop smoking

stopping smoking

give up smoking


chronic obstructive pulmonary disease


chronic obstructive airway disease

chronic obstructive lung disease

chronic airflow obstruction

chronic airflow obstructions



PICO is a framework that helps identify concepts from a focused clinical question

  • P: patient/population/problem
  • I: intervention
  • C: comparison (or standard of care)
  • O: outcome

NOTE: Not every PICO will have a comparison. 

Example Question

In adults with posttraumatic stress disorder, is yoga more effective than resistance training in reducing PTSD symptoms? 

  • P: adults with PTSD
  • I: yoga
  • C: resistance training
  • O: reduce PTSD symptoms

Connecting Search Terms

Once you have identified your main concepts and have some search terms in mind, it's a good time to begin thinking about how to connect these terms together for the search query. Use the boolean operators: AND, OR, and NOT.


Use AND to connect terms that are dissimilar to find the overlap between two different concepts. This narrows our results.

Example: children AND sugar tax AND obesity


Use OR to connect synonyms and other similar words together. This tells the database to retrieve any of the words, thus increasing the number of results.

Example: obese OR obesity OR overweight OR BMI OR body mass index


Use NOT to exclude a term from search results. However, use this boolean operator carefully and sparingly, as you might accidentally exclude relevant articles that still might mention that word.

Example: children NOT adults

Finished Search Query

Here's how you would construct a search with three different concepts using boolean operators. Group the synonyms together using OR, and then use AND to find the overlap between these topics.

(e-cigarettes OR electronic cigarettes) AND (smoking cessation OR quit smoking) AND (chronic obstructive pulmonary disease OR copd)

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