Searching for literature
Always keep in mind the aim of your literature search. If you perform a very broad search, you may find too many irrelevant articles.
A very specific search, on the other hand, may result in fewer articles, but you will risk missing some important ones.
Too many results
When retrieving too many results, there are several options to limit the number of results:
- Restrict to recent articles by using filters
- Limit to study type, e.g. with Clinical Queries
- Use narrower search terms:
- MeSH
- Search for articles that feature the MeSH term as a Major Topic with [Majr] instead of [MeSH]
- Restrict the MeSH term with one or more relevant subheading(s)
- Searches by word or phrase
- Search for title words with [ti] instead of [tiab]
- Replace search terms with more specific terms
- MeSH
Too few results
Similarly when retrieving too few results, there are several options to broaden your search:
- Check relevant articles for words (in the title and abstract) and assigned MeSH terms, and add those to your search strategy
- Relevant MeSH terms can also be found by searching for a title word AND medline[sb] (AND medline[sb] limits your search to records that have been assigned MeSH)
- Supplement your MeSH terms with
- a broader MeSH, usually one level higher (using no explode)
Example: raw foods[MeSH] OR food[MeSH:noexp] instead of raw foods[MeSH]. The MeSH Raw Foods has only been in use since 2015. Articles dating back to before 2015 are indexed using the broader term 'Food'. - a MeSH counterpart; many MeSH terms have a positive/negative counterpart
Example: cervical rib syndrome[MeSH] and cervical rib[MeSH];
mycobacterium tuberculosis[MeSH] and tuberculosis[MeSH]
- a broader MeSH, usually one level higher (using no explode)
- Broaden the search by leaving out a search concept that is too specific
- Search additionally in other (biomedical) databases, for instance Embase
Search plan for PubMed
- Search plan for PubMed (in Dutch)Use a search plan to translate your research question into a search strategy.
This involves breaking down your question into search concepts (e.g. PICO: Patient Intervention Comparison Outcome; DDO: Domain Determinant Outcome). This search plan can also be used for other databases.
How to quickly find an article
To find a specific article quickly, use:
- the PubMed ID (PMID), e.g. 24660332
- the title of the article
Searching by author
You can find publications by a specific author by entering their surname followed by their initials (max. 2), for example:
MeSH - Do's & Dont's
When you are not sure whether a MeSH term actually exists for your topic:
Do | Look up the term in the MeSH Database |
Don't | Simply add [MeSH] to the search term |
PubMed is not always smart enough to automatically match the right MeSH term.
Logbook
When working on an extensive search, you may want to keep track of the search strategy in a logbook. You can save your work with a My NCBI account (See tab: Records) or by documenting the search strategy in a Word or Excel document.
Keeping a logbook is also a good idea, if you want to translate your search to other databases, such as Embase or Cochrane.
In PubMed's Advanced search (See tab: Combine search terms) the search history can be downloaded into a .csv file. Excel can be used to convert this into columns via the tab Data > Text to columns. Next, choose separated and comma (csv means comma separated values).
Save references in EndNote
References in PubMed can easily be exported to reference managers, such as EndNote.
In EndNote:
- Open your EndNote library
In PubMed:
- Select one or more references (when no references have been selected, you can later on decide to include all references or all references on the current page)
- Click Send to > Citation manager
- Choose a Selection and click Create File
- Open the downloaded .nbib file. The references are automatically sent to the EndNote Library that is open at that moment.
PubMed references in EndNote have swapped their abbreviated journal titles with their full journal titles. To correct this, first import a list with correct journal titles in your empty EndNote library (before any references have been added).
Go to Tools > Open Term Lists > Journals Term List. Under the tab 'Lists' choose 'Journals' and 'Import List', and open pubmed_journals‑beta.txt. You can download the file via:
- pubmed_journals-beta.txt
List with PubMed journal titles for EndNote. Save this file as pubmed_journals-beta.txt.
Want to know more about EndNote?
- EndNote GuideLearn the basics of Endnote X9. EndNote is a citation management tool used by researchers, and students to store, organize and cite references.
Other available reference managers
- Compare EndNote / RefWorks / MendeleyWhich reference manager best suits your needs?