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Embase on Ovid – Overview, Example Searches and Reference Materials

Welcome to this Ovid training session. Organised by the Medical Library of the Universitätklinikum Freiburg. This Ovid training session provides a thorough and comprehensive introduction to the A&I biomedical database, Embase on Ovid through five focused searches.

Embase

Ovid Training Team

2025-01-29

115 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 training session begins with a series of exercises to review Ovid's Basic Search (NLP) search mode as well as the Advanced Searching mode. The latter focusing on free term searching techniques using the Title (TI), Abstract (AB) fields as well as the Multi-Purpose (MP) set of fields.

Then drawing upon the content and teaching approaches in and behind the learning resource OvidGO! (2), this Ovid training session will use five focused searches 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. 

The five focused searches making up this training session are as follows:

 

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

FOCUSED SEARCH 1. – DATABASE SIZE AND SHAPE

This focused search, launched on Embase on Ovid, will provide you with information on the total number of records in the database at the time the search is run. In other words, the database ‘size’. Then by separating out the database records according to their editorial status, that is by using the Status (ST) field, it is possible to view the database in terms of its constituent parts. This is what is meant here by the ‘shape’ of the database. This perspective, indeed the precise information, can also be used when constructing searches to swiftly narrow down to a specific document or publication type. For example, to conference materials or only Embase articles.

Points to note:

  • Abstracting and Indexing (A&I) databases are the most reliable and best verifiable sources of scientific information and are indispensable for systematic literature searching.
  • Generally speaking, A&I databases are composed of structured and searchable bibliographic records, many of which now increasingly also link out to their full-text original documents.
  • Composed of tens of millions of bibliographic records, these information repositories are diverse, highly structured, regularly updated and thereby relentlessly dynamic.
  • Their large size and relentless dynamism remains opaque to many users and as a result can be potentially problematic to investigating researchers and healthcare professionals.

Instructions:

  1. Logon to Ovid, select Embase <1974 to Present>, select the Advanced Search / Keyword mode.
  2. Enter the search lines for this focused search as listed below.
  3. Alternatively, having not yet logged on,  <Click here> to run this focused search above in Ovid.

docz.dz.
limit 1 to article-in-press status
limit 1 to conference abstract status
limit 1 to embase status
limit 1 to in-process status
limit 1 to in-data-review
limit 1 to in-process
limit 1 to pubmed-not-medline
limit 1 to "pubmed/medline"
limit 1 to publisher
limit 1 to "preprint (unpublished, non-peer reviewed)"
2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11

Questions:

  1. What proportion of the database are conference materials?
  2. List at least two sources of preprint servers
  3. Could you conduct a thesaurus search on the PubMed-not-MEDLINE NLM records?

FOCUSED SEARCH 2. – DATABASE CONTENT AND ITS DISPLAY

This focused search, conducted across two databases (Embase on Ovid and Ovid MEDLINE) in a single session, retrieves two versions of the same article. One version is from Embase on Ovid, the other from Ovid MEDLINE. By comparing these two versions (it is suggested in two different browser windows) you will be able to compare the similarities and differences in the respective displays of each of the records.

Points to note:

  • There are a range of similarities and differences between A&I bibliographic databases.
  • Similarities include the way in which the records are constructed, editorial processes, the use of controlled vocabularies for indexing, limits, author keyword inclusion, how the records may be searched and how the results are displayed.
  • However, differences may also be evident in these very areas, i.e. in way in which the records are constructed, editorial processes, the use of controlled vocabularies for indexing, author keyword inclusion, how the records may be searched and how the results are displayed etc.
  • An awareness of the similarities and differences between A&I bibliographic databases will make for a better understanding of them and help in the construction of search strategies.

Instructions:

  1. Logon to Ovid, select Embase <1974 to Present> and Ovid MEDLINE <1946 to Present>.
  2. Select the Advanced Search / Title mode.
  3. Enter the article title as the search for this focused search as listed below.
  4. Alternatively, having not yet logged on,  <Click here> to run this focused search above in Ovid.

[Prioritization of research questions in health crises-presentation of a concept developed during the COVID-19 pandemic]

which yields...

"[Prioritization of research questions in health crises-presentation of a concept developed during the COVID-19 pandemic]".m_titl.

Questions:

  1. Do both versions display the same Keyword Headings? If so, why is this the case?
  2. How many major topics are listed in each of the two bibliographic records?
  3. You want to send an e-mail to the corresponding author. Which record provides the relevant information?

FOCUSED SEARCH 3. – INDEXING ON EMBASE

This focused search will provide you with a quick introduction to indexing on Embase on Ovid. The focused search demonstrates how an entry term (as given in the search lines below in bold script) is mapped onto its equivalent thesaurus term in the Emtree controlled vocabulary.

Points to note:

  • In Embase all articles and other publication types are indexed.
  • Indexing is based upon the Elsevier Life Sciences Thesaurus, Emtree.
  • Records are indexed with as many Emtree terms as are required to describe their content.
  • Of note is that the Emtree thesaurus focuses specifically on diseases, drugs and devices (3 x D’s).
  • However, irrespective of its topic, each record is first indexed by automatic indexing.
  • Records pertaining to diseases, drugs and devices are then subject to further manual indexing.

Instructions:

  1. Logon to Ovid, select Embase <1974 to Present>, select the Advanced Search / Keyword mode.
  2. Enter the search lines for this focused search as listed below using the given entry terms.
  3. Alternatively, having not yet logged on,  <Click here> to run this focused search above in Ovid.

migraine/ [Entry term: migraine]
coronavirus disease 2019/ [Entry term: covid]
palbociclib/ [Entry term: Ibrance]
methylphenidate/ [Entry term: Ritalin]
coronary stent/ [Entry term: coronary stent]
nuclear magnetic resonance imaging/ [Entry term: mri]
health care access/ [Entry term: access to healthcare]
artificial intelligence/ [Entry term: artificial intelligence]

Questions:

  1. How many sub-headings are available for each of the search expressions?
  2. Would it be helpful to ‘explode’ the drug terms, ‘palbociclib’ and ‘methylphenidate’?
  3. How could you further narrow your search to only ‘drug eluting coronary stents’?

FOCUSED SEARCH 4. – DEEP INDEXING ON EMBASE

This focused search highlights Embase’s deep indexing features and functionality which are unique to Embase. While the focused search in this section consists of only three lines, it is very targeted, informationally concise and provides the basis for further in-depth investigation using Embase’s triple sub-headings.

Points to note:

  • On Embase indexing is carried out according to well-defined guidelines summarized in the Embase Indexing Guide (the current versions being 2024).
  • Manually indexed records address the full-text of the indexed document not just its title, or abstract or keywords (if available).
  • Emtree contains approximately 99,000 biomedical preferred terms as well as 548,000 synonyms ordered in 14 facets, the latter being major, broad spanning, subject categories.
  • The largest facet ‘chemicals and drugs’ includes drugs and chemical entities of every kind.
  • By contrast ‘clinical drugs’, a sub-category of ‘drugs’, are indexed in greater depth and can also be modified by using drug sub-headings.
  • Device terms are index terms used for all devices, not just therapeutic devices.

Instructions:

  1. Logon to Ovid, select Embase <1974 to Present>, select the Advanced Search / Title mode.
  2. Enter the search lines for this focused search as listed below.
  3. Alternatively, having not yet logged on,  <Click here> to run this focused search above in Ovid.

exp palbociclib/ae [Adverse Drug Reaction]
exp neutropenia/si [Side Effect]
1 and 2        

Questions:

  1. Are there benefits to exploding the Emtree term ‘palbociclib’?
  2. Are there benefits to exploding the Emtree term ‘neutropenia’?
  3. How could you focus the search without going back to the Emtree thesaurus?

FOCUSED SEARCH 5. – SEARCHING EMBASE AND OVID MEDLINE IN A SINGLE SESSION

This focused search launches a search strategy that operates across two databases, namely Embase on Ovid and Ovid MEDLINE - at the same time. The search is investigating covid vaccines and their potential side effects. The difficulty is that both of the constituent topics, i.e. covid vaccines and side effects, are treated differently by the controlled vocabularies of the target databases, Embase on Ovid and Ovid MEDLINE. The ‘Romper Search’, enabled on the Ovid platform by deploying the USE command to change databases, provides a means of searching two or more databases in a single session while still making use of the thesaurus and limits selection, specific to each of the databases. The instructions below plus the accompanying supplemental documentation describe in detail how to build such a search. Once practiced and familiar with the construction of this type of search, you could save it in Ovid My Workspace as a model example, for re-use and further development.

Points to note:

  • The regulatory environment around drug and device safety usually requires that A&I databases be consulted individually.
  • Best practice guidelines around systematic literature searching also recommends searching in separate databases.
  • Embase on Ovid and Ovid MEDLINE are both available on the Ovid platform and can be searched individually or in combination.
  • When searching the databases in combination, search expressions employing the Title (TI) or Abstract (AB) fields, either separately or in combination, yield reliable results. As does Ovid’s Basic Search (NLP) mode. So too does Ovid’s .mp (Multi-Purpose) search function. This however needs qualification as the set of fields searched across in each case differs between databases.  
  • However, where the search strategy wants to avail of the specific thesaurus qualities of the target databases and/or the database’s own selection of limits, problems of inaccurate term or terms translation or rendering may occur.
  • Named the ‘Romper Search’ Ovid has developed a search option that, utilizing the USE command, facilitates a single search across two or more databases in one session enabling searchers to avail of the databases’ specific construction, their database specific controlled vocabulary and sets of limits.

Instructions:

  1. Logon to Ovid, select firstly Ovid MEDLINE > and the Advanced Search / Keyword mode.
  2.  Enter the search expressions for this database.
  3. Park your Ovid MEDLINE results in the search history using the database segment abbreviation ‘medall’.
  4. While still in the Ovid session, next select Embase and remain in the Advanced Search / Keyword mode.
  5. Enter the search expressions for this database.   
  6. Park your Embase results in the search history using the database segment abbreviation ‘omezed’.
  7. Now re-run your parked searches through Ovid MEDLINE and Embase in the one session.
  8. Combine your parked searches using the OR operator.
  9. Add limits or impose additional search criteria, e.g. deduplication, as necessary.
  10. Alternatively, having not yet logged on,  <Click here> to run this focused search above in Ovid.

COVID-19 Vaccines/
"Drug-Related Side Effects and Adverse Reactions"/
1 and 2
3 use medall
SARS-CoV-2 vaccine/
adverse drug reaction/
5 and 6
7 use oemezd
4 or 8
remove duplicates from 9

Questions:

  1. How could you expand upon the search using free terms?
  2. Would the limit Publication Type [PT] cover clinical trials for both databases?
  3. How could you identify the duplicates within Embase only?

 

Search Stategy

docz.dz.

limit 1 to article-in-press status

limit 1 to conference abstract status

limit 1 to embase status

limit 1 to in-process status

limit 1 to in-data-review             

limit 1 to in-process

limit 1 to pubmed-not-medline

limit 1 to "pubmed/medline"

limit 1 to publisher

limit 1 to "preprint (unpublished, non-peer reviewed)"

2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11

Launch Search

Reviewers

Primary: Michael Fanning

Secondary: Michael Fanning

Review Date: 2025-01-29

Expiry Date: 2025-02-04

Original search produced by:

Ovid Training Team

Citation:

Available from: https://tools.ovid.com/ovidgo/searches/view.php?id=80