Searching PubMed

What's the difference between an advanced search and simple search? Advanced searching:

• utilizes field codes* and does not rely on Automatic Term Mapping. You control exactly what gets searched.
  • *Field codes are defined bibliographic fields like Title/Abstract or MeSH.
• uses Medical Subject Headings (MeSH) when applicable, in conjunction with text word searching.
  • Why search both? Because most things have MeSH terms, but not everything - not brand new references, or references not in MEDLINE.
• could be more comprehensive or more precise compared to a simple search. You have much more control!

When might you need to build an advanced search?

• if results from your simple search are overwhelming,
• if your simple search is not returning anything useful, or bringing in too many irrelevant results,
• if you are working on a formal project where you need comprehensive results, and/or a documented reproducible search.

Identify the different components of your search and approach your search one topic at time. Doing it all at once can get overwhelming pretty quickly.

In our example we have these two topics:

• Cardiac arrhythmias
• Drug therapy
  • In our initial search, we simply used the term "drug." However that also returned results for drug-induced cardiac arrhythmia. If you are thinking of a broad term that could have different meanings, it can help to parse it out beforehand.

Go to the Advanced Search page to access the search builder. We'll start by adding some text words to search.

Click the Field Selection box, and choose the Title/Abstract option (some also use Text Word for broader inclusion).

Enter in your terms connected with the OR operator, and use quotes for multiple word phrases. Because we are telling PubMed exactly what to search, we have to be specific. It can also be helpful to view your search details from the initial simple search for ideas.

We can use the search builder to append the "Arrhythmias, cardiac" MeSH term to our title/abstract search.

Keeping the previously added terms in the search box, click the Field Selection box and choose MeSH Terms. Then type in (or copy/paste from the search details from the previous simple search) "arrhythmias, cardiac". (Note - we'll look at how to find more MeSH terms in the next section)

Choose the "Add with OR" button, then review your full string:

Since this search string only covers heart arrhythmias, we are not going to click "Search" just yet.

Instead, click the small arrow on the Search button, and choose "Add to History."

We'll follow the same process for creating a string for drug therapy:

Now we can take our numbered search strings, and combine them!

This will leave us with only the results that intersect between the results from search #2 (heart arrhythmias) and search #3 (drug therapy).

Since we want to see the results, click "Search" instead of "Add to History" (note - this search will still be available in your history which you can access again by clicking back to the Advanced Search screen).

As you explore results, you may come across additional keywords and MeSH terms to search. That's okay - searching is an iterative process.

You can return to the Advanced search page and edit your search strings by copy/pasting the previous string into the Advanced search box, and adding the applicable terms.

Then combine your updated string with the other original string to see the change in results.