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Embase on Ovid – Refining Searches Systematically (Limits)

How to fine tune individual search lines as well as whole search queries using user-selected criteria, called ‘limits’.

Embase

Ovid Training Team

2025-03-12

33 visits

Background

Embase, produced by the academic publishing and information analytics company Elsevier B.V., is one of the largest and most comprehensive Abstracting and Indexing (A&I) database for peer-reviewed biomedical information. The Embase database covers all disciplines of medical and biomedical science as well as Allied Health subjects.

Embase on Ovid – Facts and Figures (1)

  • A bibliographic database, Embase is made up of over 41 million database records.
  • Over 1.7 million records are added each year.
  • Database records are indexed using Emtree, the Elsevier Life Science Thesaurus.
  • Conference materials, currently at over 5 million records, have been included since 2009.
  • Preprint records, from several sources, have been included since November 2021.
  • All database records are indexed using automated means and procedures.
  • Records pertaining to diseases, drugs and devices undergo further manual indexing.

Training Session Programme

This Learning Pathway series of training modules draws upon the content and teaching approaches in and behind the learning resource OvidGO! (2). Constructed around a selection of focused searches, the training programme has been designed to achieve the following two objectives,

  1. to introduce the database, Embase on Ovid, drawing upon where helpful, parallels and comparisons with Ovid MEDLINE,
  2. to discuss, demonstrate and practice the key features and functionality of the database Embase on Ovid. 

(1) Reference for the above is the Embase Indexing Guide 2024.
(2). See https://tools.ovid.com/ovidgo/       

When constructing a search question it is helpful to separate out the search terms and phrases from additional criteria that can be used to systematically reduce your database results down to a manageable number of references. Such additional criteria could be the type of publication; a journal article, a review, a specific type of review, e.g. Cochrane or ACP, a case report or even a letter or  editorial. Other additional criteria could include narrowing down the result set by language or by time. In the context of searching for information on databases, imposing such additional criteria upon a search is referred to as applying ‘limits’. Whilst the idea of employing limits is common to A&I databases, the variety and scope of the ‘limits’ options available to searchers can differ between databases.    

This Focused Search introduces an initial selection of limits available for Embase on Ovid.

The limits can be selected and applied sequentially (see lines #6,#7 and #8) or imposed in a single step (see line #9). The full range of limits available for the database you are searching in, can be viewed and selected by clicking on the Additional Limits option at the bottom of the initial selection display. You can also place the limits, most useful to you, on the initial selection display by selecting the Edit Limits option. Your selection will remain as your initial display selection for the duration of your database session. After which they will return to and re-display the default selection.

For database administrators, please note  however, that the default selection can be customized for you by Ovid Technical Support so that the default selection of limits better addresses your users’ needs. 

Practice Suggestions

  1. From the results shown in line #5, how many of them are from preprint servers?
  2. Line #6 removes from the total number of records, those that do not have abstracts. Use the NOT operator to determine how many of these records there are? Could they nevertheless still be relevant to the search query? How could you assess this?
  3. Narrow the results in line #5 to phase 3 clinical trials. Tip: Display the full list of available limits by clicking on Additional Limits. How would you do this for an equivalent search in Ovid MEDLINE?

Search Stategy

(adolescent$ or young adult$).mp. [Version 2: Ovid .mp defined group of fields]
(adhd or Attention Deficit Hyperactivity Disorder).mp.
(ritalin or methylphenidate$).mp.
(adverse effect$ or adverse event$ or untoward effect$).mp.
1 and 2 and 3 and 4
limit 5 to abstracts
limit 6 to full text
limit 7 to yr=”2020 -Current”
limit 5 to (abstracts and full text and yr=”2020 -Current”)

Launch Search

Reviewers

Primary: Michael Fanning

Secondary: Charlotte Viken

Review Date: 2025-03-12

Expiry Date: 2026-03-10

Original search produced by:

Ovid Training Team

Citation:

OvidGO! Portal. Focused Searches: Embase on Ovid – Refining Searches Systematically (Limits) [Internet]. London (UK): Ovid Training Team (Editors); 2025 [updated 2 March 2024; cited 10 March 2025]. Available from: https://tools.ovid.com/ovidgo/searches/view.php?id=106