PHCY 504 - Primary and Secondary Literature Tutorial: Embase

Let's look at the second database: Embase

Embase is:

• a large, health sciences-focused database
• a great source for drug-specific searching
• a good supplement to PubMed searches

You can access Embase from the HSL homepage, right next to the PubMed link.

Because Embase does not have a free version it must be accessed through the Library any time you would like to use it, or you can bookmark the Library's Embase link. This link will take you to the quick search page, where you can type in your initial search terms.

When you start a search in Embase, Embase defaults to its "search as broadly as possible" option, which will automatically map your search to any applicable Emtree terms if they exist. For example, if you type in type 2 diabetes, you'll see that Embase suggests using the Emtree term non-insulin dependent diabetes mellitus. Unlike with PubMed you will want to go ahead and put the terms that Embase suggests as Emtree terms into quotes.  Embase uses 'single quotes', while Pubmed uses "double quotes".

Embase will search as broadly as possible for your first search, for all subsequent searches this box will be unchecked. Make sure you recheck it before each search if you want to continue searching broadly.

Why do we use quotes with Embase and not with PubMed?

In PubMed, using quotes turns off the mapping to MeSH (Medical Subject Headings) so you don't want to use quotes when starting a search. However, Embase will only search for Emtree terms one word at a time, so in order for Embase to find the full entry term you'll need to put quotes around each search term or phrase from the first time you run the search.

Embase makes it easy to find Emtree terms with its auto-suggest feature; however, it is a good idea to check out the Emtree database, as this will give you additional information about each term. To get to the Emtree database from the search page, select Emtree at the top of the Embase search page.

If you search for type 2 diabetes here, it will once again suggest non-insulin-dependent diabetes mellitus. If you click on this term, it will take you to the Emtree entry for this term, which will show you where the term is in the tree as well as the history of the term, synonyms for the term, and some dictionary definitions for the term. The synonyms in Emtree tend to be a little bit more robust than the synonyms in MeSH so it's a good idea to take a look at the list when you're looking for synonyms. 

One of Embase’s other interesting features is its drug search.

To use Embase's drug search-specific headings, select "drug" from the search menu on the left. Here you can enter either a drug name or a drug class (e.g., linagliptin or dipeptidyl peptidase-4 inhibitor). You also have the option to add things like drug field, where you can search for a drug manufacturer or trade name, drug subheadings (something like an adverse drug reaction  or pharmacokinetics), or the route of administration.

For example, you can search for adverse drug reactions to metformin administered orally.

Embase also makes it easy to combine searches. Once you have several terms or strings of terms on each line, you can use AND, OR, or NOT to combine your searches.

For example, if you wanted to search for diabetes treated with dpp-4 inhibitors or metformin in the search below, you could search for  #2 AND (#3 OR #4).

Embase also contains search filters similar to the ones in PubMed. These filters are found along the left-hand side of your search results page and include options that you can also find in PubMed, like:

• Age
• Gender
• Study types
• Publication types

Embase also contains additional filters that you cannot find in PubMed. These allow you to narrow your search to a specific drug, disease, device, or specific subheadings.

To sum up Emtree searching, there are three ways to look for Emtree terms:

1. type a term into the Embase search bar and Emtree will suggest a term for you
2. search within the Emtree database
3. look at the Emtree terms assigned to a relevant article

A few final Embase tips:

1. Always start with the advanced search option.
2. If you are looking for synonyms for your term, the Emtree entry generally has a wider range of synonyms than the MeSH database in PubMed, so it's a great place to start.
3. Use single quotes when searching for phrases in Embase.
4. Once you have executed your search, review your search results each time to make sure they're pulling articles or studies that are of interest to you
5. If you would like more information on searching Embase these are a few sources you can try:
   1. Tips on using Embase in the HSL's Searching Embase guide: https://guides.lib.unc.edu/embase/intro
   2. Embase help section from Elsevier: http://help.elsevier.com/app/answers/list/p/9754