A Brief Introduction to PubMed
Do
Don't
Information provided by the National Library of Medicine (NLM). This information and more can be found on the NLM New PubMed website.
Basic Search Features
PubMed searches more than just the words or phrases you type into Basic search. This is called Automatic Term Mapping. Check what other terms PubMed is automatically searching; you can troubleshoot a query in which results have gone off the rails. Follow the steps below.
1. Type in your search terms (in this example "de quervain's tenosynovitis treatment")
2. On the results page, click "Advanced" under the search bar.
3. Scroll down to the "History and Search Details" section. Click on the > below the Details heading.
4. View the full search that PubMed is running: all MeSH terms used, as well as synonyms, translations, and British / American automatic term mapping.
1. Add first search term to query box.
2. Add additional search term into "enter a search term" box. Use dropdown arrow in blue "Add" box to decide whether you want the first and second search terms to be connected with Boolean operators "AND", "OR", or "NOT".
3. Add more search terms.
Pro Tip: Before you start searching, write key concepts and synonyms out (in PICO-style format if applicable). Record terms and synonyms in a simple table with rows and columns. Excel, scratch paper, Google Doc, it's your preference.
4. When finished adding search terms, click "search" next to query box to see results.
Instead of hitting the search button, use the dropdown arrow and select "add to history".
Scroll to Search History / Search details section. View number of results for each query in your Search History. Results numbers are indicators; they let you know whether you should expand or refine your search terms, based on the number of results in Search History.
So you've created several simple searches and added them to search history. Now what? Combine your simple searches into a large, complex search that focuses on the intersections between several simple searches. There are two methods for creating complex searches:
1. On Advanced Search page, scroll down to Search History. Click the "..." under the Actions heading of one of the searches that you would like to mix and match.
Select "Add query." Your search moves into the query box.
Continue to add small searches to the query box in the same way. Choose a Boolean operator ("AND", "OR", and "NOT") as you combine searches. Example: connecting simple searches with AND looks for intersections between those simple searches.
Run your new search through PubMed, or add it to your history. In the screenshots, you can see that combining searches with AND produced a much smaller number of results than either of the two simple searches individually. Depending on your searches and the Boolean operator that you use to connect them, the number of results may be much larger or smaller.
Remember:
OR
2. Alternative Approach: Use Boolean operators to combine search numbers in the query box. Search numbers can be found under Search History.
Run search through PubMed, or add to your search history. In the screenshot below, note that both methods of creating complex searches will return the same results.
More info on Advanced Search can be found on the Advanced Search section of the PubMed User Guide.
NLM New PubMed includes video walk-through of this info.
In PubMed results' left navigation, you'll find filters. These filters narrow your search results.
You can filter results based on publication date, article type, and text availability. Select "additional filters" option at the bottom of the sidebar to see more filter options.
Select filters to apply to your search.
1. select broad category of filter (article type, age, etc.)
2. check off specific filters, and
3. click "show" to see those filters appear on your search screen.
Additional filters appear in left navigation, beneath default filters.
Newly applied filters appear at top of search screen, with a yellow highlight around them. Note: when filters within the same category are applied (i.e. when multiple boxes are checked under one heading), PubMed is searching using "OR" so you will have more results with more boxes checked in one category.
Remove all filters by selecting "clear all." If you are looking to remove individual filters, un-check them in the left navigation.
MeSH (Medical Subject Headings)
"MeSH (Medical Subject Headings) is the NLM controlled vocabulary thesaurus used for indexing articles for PubMed." In other words, MeSH is a taxonomy designed to help researchers find studies based on subject content. Searching with MeSH is a helpful and thorough complement to searching with keywords and phrases.
Example: influenza[tiab] OR "influenza, human"[Mesh]
This example search returns studies including keyword influenza anywhere in the title or abstract, OR results indexed or "tagged" by PubMed's algorithm as containing substantial content on human influenza.
You can use proximity searching to search for multiple terms appearing in any order within a specified distance of one another in the [Title] or [Title/Abstract] fields.
To create a proximity search in PubMed, enter your terms using the following format:
"search terms"[field:~N]
Proximity search is not compatible with truncation.
The new PubMed interface is optimized for use on mobile devices. Full text access is available on mobile devices.
