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Gerstein Science Information Centre

Searching the Literature: A Guide to Comprehensive Searching in the Health Sciences

Students and researchers in the health sciences are often required to conduct comprehensive searches of the literature. Follow the steps in this guide to learn how this process works.

Introduction to Translation

Once you have conducted your search in your first database (usually Ovid MEDLINE), it is time to translate your search into the other databases you have selected. By translating your search, you do not need to start from scratch for each new database. Unfortunately, this is not as simple as copying and pasting your MEDLINE search. Each database has slightly different rules and systems for searching so you need to adapt your search strategy for each platform.  

Why Translate?

For a knowledge synthesis such as a systematic review, it is methodologically required to search at least three databases. Cochrane recommends searching at least MEDLINE, Embase, and CENTRAL to identify trials, but the databases you choose will depend on your specific research question, review type, and relevant inclusion criteria 

There are several reasons why translating is useful and necessary.  

  • Databases often have some overlap in content, but each one also contains extensive unique materials as shown in the diagram below.

  • Articles may be in multiple databases but indexed differently in each one, meaning you may miss it in one database, but locate it in another. For example, an article might have 10 subject headings in MEDLINE and 25 subject headings in EMBASE.  

  • Searching multiple databases helps to reduce biases such as publication bias and location bias. Publication bias describes the phenomenon in which studies with certain results are more likely to be published. Location bias describes differences in ease of access and levels of indexing depending on a study’s results. One example of location bias is that positive results are more likely to be found in higher impact journals which are easier to find.  

Further details about the importance of searching multiple databases are described in the “Choose your database (s)” section of this guide. 

How to Translate

It is important to consider all the different elements of a search that may need to be translated. Certain elements are always translated including subject headings, operators/symbols, search field, and filters/limits. Minimum search concepts are sometimes translated and sometimes stay the same. Text words remain the same regardless of database. Below are more details about how each aspect of a search is translated. 


Minimum Search Concepts  

The first step is translating your minimum search concepts. For some databases, your minimum search concepts will be the same.  

  • For example, if you are translating from MEDLINE to EMBASE and your minimum search concepts are “Children”, “fever” and “acetaminophen”, the concepts will remain the same  

  • In contrast, if you are translating from MEDLINE to EBSCO Child Development and Adolescent Studies, you could remove the concept “children” from your search because all articles in that database are relevant to your chosen population.   

MEDLINE and EMBASE Minimum Search Concepts 

EBSCO Child Development and Adolescent Studies Minimum Search Concepts 

Subject Headings  

  • Each database uses different subject headings  

  • Subject headings have different names in different databases. For example, MEDLINE calls them MeSH and EMBASE calls them Emtree.  

  • Even in cases where the subject heading is the same, check the scope note because they may define terms differently.   

  • For example, MEDLINE defines child as “A person 6 to 12 years of age” and CINAHL defines child as “A person of either sex between the time of birth and adolescence.”   

MEDLINE Scope Note for "Child" Subject Heading 

CINAHL Scope Note for "Child" Subject Heading 


Making Adjustments   

  • Your search is not complete until you have finished translating to all the databases  

  • You may find new synonyms as you translate, and you will need to go back and adapt the original search with this added information.   

  • Save your translations in each database as you go. When all your searches are complete, you are ready to export your results 

This work is openly licensed via CC BY-NC-SA 4.0For information on this guide contact Erica Nekolaichuk, Faculty Liaison & Instruction Librarian at the Gerstein Science Information Centre.