PHCY 504 - Primary and Secondary Literature Tutorial: PubMed

Let's look at the first database: PubMed.

PubMed is:

• is an interface that allows you to search MEDLINE
• one of the best resources for primary literature (studies) and secondary literature (reviews) in the biomedical sciences
• your best resource for systematically locating recently published articles.

To get to PubMed from the HSL page, click on the PubMed link on the homepage or go to the pharmacy guide and then select the link to PubMed. It is very important that you always go to library resources like PubMed and other databases through an HSL or UNC libraries link. Otherwise you will not have access to full text resources via UNC. You may also want to bookmark the link to the Pharmacy guide, as it contains links to many of the sources you will need during your time at the School of Pharmacy.

Now, type in a search term into the main search bar. Once you have typed in your search (in this instance, aspirin), scroll down the results page to see the articles found in your search. 

Ideally, what you want to see on your search results page is a reasonable number of relevant-looking articles. PubMed will map your search terms behind the scenes to MeSH terms, or "medical subject headings," to help you find articles on your topic that may not have used your search term in their title or abstract/article summary. MeSH terms are one of the things that makes searching PubMed more powerful than using a search engine like Google.

MeSH is the controlled vocabulary used for indexing in PubMed. MeSH terminology provides a consistent way to retrieve information where several different terms may be used for the same concept. For example, an author may say "heart attack" or "myocardial infarction" for the same event. Finding the correct MeSH term is the key to retrieving relevant articles even when authors use different words or spellings for the same topic.

One thing you do not want to do when you are initially searching PubMed is to use quotes around your search terms if you want PubMed to try to find the MeSH term. Using quotes tells PubMed to search for exactly what you put into the search box and not to do what we want it to do in this instance, which is to see if there is a MeSH term for your search. Once you have determined what the MeSH terms are, you can go back and add your original term in quotes if you need more control over your search results. 

If you want to see how PubMed is interpreting your search, see your search history, or run a more complicated search, you can use the PubMed Advanced Search page.

On the PubMed Advanced Search page I can see how PubMed interpreted my original search on Aspirin by clicking on the Details button next to the search in my History. This shows me the MeSH term applied to my initial search as well as how PubMed ran my search. To edit your search and run it again, click on Actions and then Add Query and PubMed will add your original search terms to the Search Box. You can edit those terms and add additional terms and then click Search to go back to the Search Results page.

If you think PubMed did not apply the correct MeSH term or you want to see if there are other MeSH terms you might want to add to your search, you can dig a little deeper by searching the MeSH database. You can find the MeSH database by going back to the PubMed homepage and selecting the "MeSH Database" link.

Once you're in the MeSH database, type in your search term and see if there are any suggestions. In this case, PubMed will provide a list of potential MeSH terms and I can select the one I want to look at in more detail and/or use in PubMed for a search.

One way to narrow your search to the most relevant articles in PubMed is to use PubMed's built-in filters along the left-hand side of the search results page. There are several ways to limit your search; the PubMed defaults include:

• study type
• publication date

You can also use the "Show additional filters" link to add options like:

• species
• language
• sex
• age
• more study types

PubMed also allows you to limit by text availability, but it is not advisable to use this filter. UNC pays for many more articles than are available freely in PubMed to the general public, so using this filter would hide all of those additional articles that you have access to as a UNC affiliate.

1. If you find an article that you would like to read, you can use the full text links to find a PDF of the article. In PubMed, there is usually a publisher's link and the button. You will generally want to choose the button, as this will link you back to our catalog and the resources that UNC pays for. If you are off campus, you can log in with your onyen and password to see the article.
2. If the article's title says withdrawn, that means that the article contains errors or other inaccuracies and should not be used.
3. If an article title is in brackets, then that article is in another language, and you should probably find another article unless you can read that language.

To sum up PubMed searching:

1. Don't use quotes around your individual search terms, only for long phrases.
2. Check your search details on the advanced search page each time you run a search. 
3. If your search isn't returning relevant results or is not returning any results, use the MeSH databases to look for additional terms. 

A few final PubMed tips:

1. Use the Find at UNC button to access the full text articles for free. 
2. Use filters as needed to specify a date range and consider using other helpful filters like limiting to certain study types, studies on humans, etc.
3. You can visit these links if you want more help on using PubMed:
   1. Health Sciences Library's Searching PubMed guide: https://guides.lib.unc.edu/search-pubmed 
   2. Tutorials from the National Library of Medicine (NLM): https://www.nlm.nih.gov/bsd/disted/pubmedtutorial/cover.html
   3. NLM's Animated Tutorials: https://www.nlm.nih.gov/bsd/disted/linkout_for_libraries/loforlib.html#qtex