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Systematic Reviews and other Knowledge Synthesis: Conduct search

This guide covers the basics of conducting a systematic review and other types of knowledge synthesis

Conduct search

The part we've all been waiting for! It's time to search! It is highly recommended to enlist the help of a medical/research librarian for this step. 

  • Search the databases
    • Follow your search protocol
    • Search in multiple databases (you must include a database that covers MEDLINE. You can use PubMed, Ovid or Embase for this. Briscoe Library does not currently have access to Embase.)
    • It is recommended that you enlist the help of a librarian to design and possibly run the searches
    • Record your results in the PRISMA flow chart
  • Search the grey literature
    • Government documents may be applicable, but may not appear in the databases
    • Advocacy groups, Industry reports, and more
    • May not be applicable to your question
  • Perform hand searching
    • Not all journals are published electronically
    • Not all trial reports are accessible through the databases
    • Requires going through a journal or conference proceeding page by page
  • Contact experts
    • If researchers have unpublished studies that may be valuable to you
    • Helps combat publication bias


Managing and deduplicating references - see box below.

Choose databases

According to the Cochrane Handbook, a search should be, "as extensive as possible in order to reduce the risk of reporting bias and to identify as much relevant evidence as possible (Lefebvre et al., 2023, Chapter 4)."

  • A minimum of three databases is recommended
  • The search should be reproducible

You must include a database that covers MEDLINE. You can use PubMed, Ovid or Embase for this. However, Briscoe Library does not currently have access to Embase.

Other commonly used databases include:

A selection of subject specific databases:

See the library's list: A-Z Databases for a full list of databases the library subscribes to.

Record results from your searches in a PRISMA flow chart 


See this guide for help creating search strategies: Systematic Reviews: Step 3: Conduct Literature Searches

Grey literature

Grey Literature is probably one of the trickiest parts of the SR, and you may not need it for your assignment. However, if you do, see this fabulous guide from UPenn on finding, evaluating, and using GL.

Examples of grey literature:

  • conference abstracts
  • presentations
  • proceedings
  • unpublished trial data
  • regulatory data
  • government publications
  • reports
  • dissertations/theses


Handsearching is the process of manually looking through medical journals or conference publications for relevant papers. This should be done by the subject experts.

This is a supplemental step and is not always needed for every review. The team should determine if it will be valuable for their review.

Another form of handsearching is searching the reference list of studies included in the review.

Search standards

Managing references

After finding articles, you will need to organize them and then deduplicate them. EndNote is a good tools for both of those tasks.

EndNote is available for UT Health San Antonio Faculty, Staff, and Students from UT Health San Antonio Information Technology (UTHSA-IT). It is available for Windows and Mac OSX. See this EndNote guide for help installing it.


  1. Export files from each database searched into your EndNote library (see this guide from UNC on exporting from different databases)
  2. Merge files into one library
  3. Deduplicate files
  4. Import files into screening tool (See the "Select studies" tab for more on this)


Deduplication with EndNote:

Record the number of duplicates that you delete!

Option 1: Select the References menu, then Find Duplicates. A window will appear showing a side by side comparison of duplicates. Any differences between records will be highlighted. You may copy information from one record to another. Select Keep This Record for one and the other will be sent to the Trash or select Skip to keep both. 

Option 2: Select the References menu, then Find Duplicates. Select Cancel on the appearing window to see a list of duplicates. The newer versions of each duplicate will be highlighted. You may drag the highlighted references to the Trash (on the left).

After completing Option 1 or 2, sort All References by author or title to identify any remaining duplicates. You may change the default deduplication settings by selecting the Edit menu, Preferences, then Duplicates.

Document your search

The Cochrane Handbooks states, " The search process (including the sources searched, when, by whom, and using which terms) needs to be documented in enough detail throughout the process to ensure that it can be reported correctly in the review, to the extent that all the searches of all the databases are reproducible (Lefebvre et al., 2023, Chapter 4)."


The PRISMA-S Group has developed an extension to PRISMA to help researchers document their literature searches for systematic and other types of reviews.

PRISMA for reporting your search strategies

Explanation and elaborations can be found here:

PRISMA-S: An extension to the PRISMA Statement for reporting literature searches in systematic reviews