 Hi, my name is Alex, I'm a librarian at the University of Alabama, and in this tutorial I'm going to continue to talk about using mesh terminology in order to search for articles on PubMed. In a previous tutorial, we introduced mesh terminology and how to use it for searching. Today we'll expand on that. Let's start by going back to the mesh database. A search for brain cancer brings back brain neoplasms as the preferred term, the mesh heading. If I add this to the search builder, it will retrieve all 150,000 articles tagged with this mesh heading. Let's look at the mesh terms for this article. Every article will always have multiple mesh terms assigned to it, but they will also have major headings. If you want to see which mesh term is considered the major heading, you just look for the asterisk, in this case brain neoplasms epidemiology. This is what this article is primarily about. You can use this major heading concept to your advantage when searching. If you want to make sure that any article you find has brain neoplasms as a major heading, you can choose to limit your search to mesh major heading in search PubMed. Our previous search found around 150,000 articles. This one retrieves around 125,000. So that means that 25,000 references in the other search were articles that were at least partially about brain cancer, but were not primarily about brain cancer. That also brings up another aspect of mesh headings, which is that they are organized in a hierarchical fashion. Let's scroll down and look at what I'm talking about. Below diseases are neoplasms, and in turn, below neoplasms are brain neoplasms. Below that are a number of other narrower headings which are related to brain neoplasms. So why am I showing you this? Well, the default mesh search for brain neoplasms includes all the headings that are grouped below it in the hierarchy. If you'd like, you can tell PubMed to not include those terms in your search. To do that, just choose to not include those terms. This will be a slightly narrower search. So I've talked about a lot of aspects of this mesh heading page, but I haven't talked about the subheadings. As you can see, this brain neoplasm heading has a number of subheadings, diet therapy, prevention and control, etc. You can choose to search for just one of these subheadings, which will be a much narrower search. Or you could search for a number of them. In this case, I would usually want to use the Boolean connector OR, so I could add the subheading metabolism and maybe prevention and control. And this search would look for either of these subheadings and would therefore be a broader search. The final thing I'll point out is you can use the mesh headings directly from the advanced search if you'd like. The search fields on the advanced search include mesh major topic, subheadings and terms. And, of course, helps to know what the terminology actually is, although it will also map terms for you. And that's all for this tutorial. Hopefully you now have a good understanding of how to use mesh terminology. And remember, if you have a question, just ask a librarian.