• Guide to running a basic search. 
• Guide to running an advanced search using Medical Subject Headings (MeSH). 
• Guide to refining your search. 
• Instructional videos.
• Create a search alert to stay on top of the literature.

Building a search in PubMed

Example topic: Effect of traffic-related air pollution on blood pressure

Learn more about crafting an answerable research question.

Gather separate concepts:

1. Blood pressure, hypertension
2. Vehicle exhaust, diesel exhaust, vehicle emissions, traffic, etc. 

Technique A: Search Separately and Combine in Final Step

1. Search 1: blood pressure OR hypertension
2. Search 2: exhaust OR emissions OR pollution OR diesel
3. Search 3: vehicle* OR traffic
4. Search 4: #1 AND #2 AND #3

Using Search History

Click on Advanced Search from the PubMed home page. Combine your previous searches by typing the set numbers, e.g., #1 AND #2 AND #3, or combine a previous search with new keywords.

Search History is located below the Search Builder, on the Advanced Search page. 

Technique B: Search in One Step

1. Search 1: (blood pressure OR hypertension) AND (exhaust OR emissions OR pollution OR diesel) AND (vehicle* OR traffic)

While this strategy appears simple, it is much more easily done incorrectly. Note the necessity of parenthesis to tell the database which terms to group as synonyms; if parentheses are placed incorrectly or forgotten, your search results will be odd or you may not realize that you're missing out on a significant part of the literature. 

Filters

Select filters to limit results, such as publication dates (last 5 or 10 years, or custom range), English language, Humans, articles concerning particular age groups: child, adolescent, adult etc., specific research study types, for example, comparative study, or randomized controlled trials.

Click Show additional filters to display more filter options.

Note that you may miss out on relevant literature because you set a date filter of 10 years, but seminal research was conducted 12 years ago. 

Advanced Searching

Use the Search Builder (on the Advanced Search screen) to search for words in specific fields of the citation/abstract, such as words in the title, words in title/abstract (which includes author keywords), or particular Medical Subject Heading (MeSH) terms.

Notes About Boolean Operators (OR, AND, NOT)

OR

Use “OR” when searching synonyms or alternative terms. Articles containing any of the ORed words will appear in the search results. 

(wine OR chocolate) AND cardiovascular effects

AND

Terms connected with “AND” must all show up in each article retrieved.

NOT

“NOT” will remove articles containing particular terms. 

(hiv AND cancer) NOT children – eliminates articles discussing children, also excludes articles that discuss both adults and children.

Combining Boolean Operators

You can combine terms into one search statement successfully by placing the terms in parentheses that you want to process first:

Blood pressure AND (vehicle* OR traffic) AND (emissions OR particulates OR exhaust)

MeSH Database

Use the MeSH Database to locate appropriate Medical Subject Headings (MeSH) and then to narrow your search focus.

Example: Use MeSH to do a search on indoor air pollution and asthma in children

1. Look up indoor air pollution in MeSH to find the appropriate MeSH heading for this concept. Click the entry to see the definition and subheadings for further narrowing the topic.
2. Check the box next to the ‘adverse effects’ subheading
3. Click on the ‘Send To’ arrow and select ‘Send to Search Box’
4. Look up asthma in MeSH.  May add focusing subheadings, such as ‘prevention & control’ or ‘epidemiology’.  Add to search box.
5. Click “Search PubMed” to view the results.

MeSH is useful for searching effectively for countries or regions ex. Georgia (the country), Africa South of the Sahara, for articles discussing any country within that region, and for searching for articles about specific population or ethnic groups.

For most complete search, use both subject headings and text words (keywords).

Advanced Tip

Type in search field [tags] to qualify your terms: pesticide drift[tw] AND environmental exposure[mh] (finds articles where pesticide drift appears as Text Words (title, abstract, or MeSH term) and where environmental exposure is a MeSH term. Title=[ti], Author=[au], title/abstract=[tiab] etc. Find complete list of search field tags in PubMed Help. 

Special PubMed Search Filters

CLINICAL QUERIES and TOPIC-SPECIFIC QUERIES

– find under PubMed Tools on PubMed home page

Clinical Queries

Searching Clinical Queries will help locate the best research articles for therapy, diagnosis, etiology or prognosis searches, or search for systematic reviews.

Topic-Specific Queries

Topic-Specific Queries includes health services research filters for concepts such as health care quality, or health care costs, or comparative effectiveness research. 

My NCBI

Create a free My NCBI account so you can save searches to re-run or have emailed as alerts, or save article citations as collections or bibliographies. See the guide, My NCBI, for directions. Set Filters/Preferences to display ‘UW Online’ and ‘Check for Full Text’ links to UW library holdings (see Search Filters/Site Preferences tab).

PubMed Tips

Try This ...	In PubMed ...  (link to PubMed from hsl.uw.edu for best full-text access)
Use Filters	Limit your search by using the Filters on the Results page sidebar.  Choose the restrictions for your search, e.g., specific language, article type (e.g., randomized controlled trials, review), ages, date, etc. Note: Filters remain in place until you change or remove them. Limits other than language or date will exclude NEW records that are "in process" or "supplied by Publisher."
Search by phrase ("")	Add quotations around words to tell PubMed to find an exact phrase.  Note: using quotations (“”) turns off automatic term mapping.
Search for words in a specific field	Use the Advanced Search Builder or use the correct field tag in square brackets:   Search for words in article titles    Ex: a1c[ti] AND diabetes[ti] Search for an author    Ex: Berg AO[au]   To see all field tags go to PubMed Help (www.ncbi.nlm.nih.gov/books/NBK3827/#pubmedhelp.Search_Field_Descrip)
Find Related Citations	Related articles, citations closely related to the original citation, are available in the Abstract format. These citations are displayed by relevancy and may be reviewed and added to the clipboard, saved or printed.
Use Clinical Queries specialized searches to find evidence-based citations	Enter your search terms and evidence-filtered citations will appear under Clinical Study Categories, Systematic Reviews, or Medical Genetics. For health services research and other filters see Topic-specific Queries. Find filters on the PubMed home page or under More Resources at the top of the Advanced Search screen.
Construct a search using MeSH terms MeSH terms, Medical Subject Headings, are assigned to all indexed articles in PubMed; they are a key to finding relevant articles	Once you've identified an article that looks relevant, take a look at the article's MeSH terms. In the abstract view, click on the + next to Publication Types, MeSH terms. Click on the term to send it to the PubMed search box. You may send additional terms to the PubMed search box (use AND to combine; OR for synonyms). You may add keywords to your search to narrow your results. If you know a MeSH term enter in the search box followed by the field tag in square brackets [mh] MeSH heading; [majr] major MeSH heading    Ex:  mass screening[mh] AND cardiovascular diseases[majr]   Use subheadings to further refine search results   Ex:  mass screening[mh] AND          cardiovascular diseases/diagnosis[majr]

Reminders

• Use of MeSH terms excludes most current (not yet indexed) or unindexed citations.
• Truncation and use of quotations (“”) for phrases turns off automatic term mapping.
• Filters remain in place until you change or remove them. Filters other than language or date will exclude NEW records that are "in process" or "supplied by Publisher."
• Save your search using MyNCBI or download search strategy from the Advanced Search/History page.
• If the UW does not subscribe to the journal, you can follow the link under Get a Copy for obtaining the article at no charge.

Database Selection

• Default databases to search:  PubMed, Embase, and Web of Science.
• Consider conducting a cited reference search in Web of Science or Scopus.
• For additional specialty databases see HSL Toolkits or contact Sarah.
• For more information see Develop Search Strategy tab on HSL Systematic Review Guide.

Hints for Improving Search Results

No References or Too Few References

• Look for misspellings in your strategy.
• Decrease the number of concepts searched.
• Try a broader search term.
• Use a term from the thesaurus (i.e., MeSH or subject heading list) for searching.
• Use the Related Articles feature.
• Increase the number of synonyms or alternatives for a term.
• Use a truncation symbol at the end of a term to pick up variant endings.  The asterisk (*) is the truncation symbol used in PubMed.  Example:  asthm* will retrieve asthma or asthmatic. Note:  using truncation ‘turns off’ automatic mapping which can result in missing MeSH terms.
• Try a different database.

Too Many References

• Choose the most specific subject headings or most significant key words.
• Use subheadings to narrow the focus of the subject heading if appropriate.
• Add additional concepts to your search to narrow focus.
• Make a MeSH term the main/major focus of the article  [majr]
• Select specific article types ( e.g. randomized controlled trials or reviews) using Filters.
• Limit your search by language, age group, current years, etc. by using Filters.
• Ask for significant words to be in the TITLE of the article.

Other Resources:

• For additional PubMed search help see PubMed at the UW
• Citation management support