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Embase (English): Emtree

This LibGuide offers an overview of the various search options of the biomedical database Embase on the Ovid platform.

What is Emtree?

Emtree is the collection of standardized keywords in Embase.

  • Emtree terms are added to articles to describe the content of an article in a uniform way.
  • Articles that are entered in Embase are automatically assigned Emtree terms (using an algorithm). These Emtree terms are then manually checked and corrected by Embase indexers.

Why do I need to search with Emtree?

Searching with an Emtree term will return (all) publications on a certain topic, irrespective of the author's choice of words.

Pollen DandelionExample: Searching with the Emtree term pollen allergy will find all articles on pollen allergy, even if it is described as 'hay fever' or 'pollen sensitivity' in the article. If you were to search for the word pollen allergy, you would miss these articles.

How come searching with Emtree alone is not enough?

  • The latest articles are missing
    New articles have only been automatically indexed. This automatic pre-indexation with Emtree terms may contain errors. By additionally searching for words in the title and abstract, you will reduce the risk of missing relevant articles.
  • There is no appropriate Emtree term
    Sometimes there is no Emtree term for the concept you are interested in. In that case, it is important to search (additionally) for relevant words in the title and abstract.

A sensitive search strategy in Embase is built up by Emtree term searches and searches by word (See the next page: Search by Word).

How to find, select and search with an Emtree term

In the Advanced Search, the option Map Term to Subject Heading is checked by default, which will direct Embase to search for relevant Emtree terms. As an example we will look up 'influenza'.

Screenshot Advanced Search - Emtree term search

Next, Embase displays a list of Emtree term suggestions. Choose the Emtree term that best suits your topic. By clicking on the Emtree term, you are directed to a new page with more information on this Emtree term (thesaurus).

Screenshot Emtree terms suggestions

The thesaurus shows additional information about an Emtree term:

  • [Used For] - here you can find the synonyms that are listed under the Emtree term
  • Broader terms - more general Emtree terms
    Example: 'influenza' is a type of 'orthomyxovirus infection' and also a type of 'respiratory tract infection'.
  • Narrower terms - more specific Emtree terms
    Example: 'influenza' can be divided into subtypes, e.g. 'influenza A', 'influenza B', etc.

Screenshot thesaurus influenza

  • Explode
    By checking 'Explode', Embase will search with the checked Emtree term and all narrower terms.
    Example: Here, you will also find articles on 'swine influenza'.
  • Focus
    Focus limits your results to articles where the Emtree term is the major topic.
    For a first exploratory search we do not recommend this option.

TipBy browsing the broader and narrower terms, you can sometimes find a more suitable Emtree term and/or find additionally relevant Emtree terms.

Subheadings are perspectives to limit an Emtree term. For a first exploratory search we do not recommend the use of subheadings. If you do not check any subheading, Embase will include all subheadings.

Screenshot subheadings

Click on Search History to display previous searches. Emtree terms are indicated by a slash / at the end of the word or phrase. The exp before an Emtree term indicates that all narrower terms are also included in the search (See tab: 3. Thesaurus).

Additionally, if you know the desired Emtree term, you can also search directly with the Emtree term by typing for example exp influenza/ in the search bar.

Screenshot Search History

Demo: searching with Emtree (4:32)

Info Watch the video above for a demo on how to search with thesaurus terms (such as Emtree) on the Ovid platform. This video takes MeSH in MEDLINE as an example, but the concept is the same for Emtree in Embase. The demo can also be played in full screen mode.