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Systematic Review Resources: PI(E)CES: Exploring the Literature

This guide is designed to help you get started on a systematic review and provide guidance on a wide variety of resources.

Searching the journal literature

Types of Searching
There are a minimum of four kinds of searching that go into a systematic review:

Preliminary Search – This is the kind of searching most people do when they start thinking about conducting a systematic review. If you need help with a preliminary search, we can help. However, the results from a preliminary search are not exhaustive, and should not be used as the sole source of data for your systematic review. The goals of the preliminary search include: identifying existing reviews, assessing volume of potentially relevant studies (assume an exhaustive search will identify about 2-3 times the number located in a preliminary search), locate at least 2-5 example articles that meet your review criteria.
Exhaustive Database and Grey Literature Search – This is the search designed by a librarian trained on how to design searches for systematic reviews. One goal of an exhaustive search is to Identify all publications and as much grey literature as possible that meet study requirements. Another goal is to document and report the exhaustive search in such a way that it can be replicated for updates and reproduced by others after publication. See the Texas Medical Center Library's S.R. Database and Resources Libguide.
Hand SearchIdentify grey literature like conference proceedings, abstracts for posters, and presented papers not indexed in online databases. Sources to hand search include: subject specific professional association websites, major relevant journals, bibliographies of all included studies, and bibliographies of on topic reviews. It is best for the subject experts to do the hand searching since they are most likely to have access to conference archives on professional society websites. It is important to document all sources searched by hand and what was located for reporting and creating the PRISMA Flow Diagram.
Contact Experts – The goal of contacting experts is to determine if more than one paper had been published on the same study and to identify unregistered studies with unpublished results or potential results. 


Caveats for searching

It is important to search two to five databases individually. Only searching one database or using the Library's Find It Fast is not acceptable. Which databases and how many you choose to search depends on the topic of the systematic review. The databases listed below cover tens of thousands of journals and even special reports that get indexed by the databases.  Work efficiently-- start with journals, then look at other resources. You will need to be affiliated with the University of Texas School of Public Health to access these resources. Each database has rules that govern how it operates. It can be helpful to review the rules before searching. Ultimately, be sure you consult with a librarian or information specialist before undertaking your searches for original studies. Searching online databases is a specific skill that librarians are trained to do.  A librarian does not have to be an expert in the subject matter-- that is your job. But a librarian will know the best way to formulate a search strategy which yields the best results. Schedule a consultation with the a Texas Medical Center Library Liaison to discuss your research needs. Be prepared before the consultation by completing the Systematic Review Self-Assessment Checklist.

Database Searching Tips

1. Identify main concepts and keywords. Search the main concepts first, then limit further as necessary.

2. Find Synonyms (Boolean OR broadens the search to include alternative keywords or subject thesaurus terms):

  • pediatrics OR children
  • teenagers OR adolescents

3. AND (Boolean AND joins concepts and narrows the search)  :

  • occupational therapy AND children
  • stress AND (occupation OR job)

4. Be aware of differences in American and English spelling and terminology. Most databases use American spelling and terminology as preferred subject terms.

5. Use Truncation (putting * at the end of a word stem will search all forms of the word):

  • disab* (disability, disabilities, disabled)
  • child* (child, children, childhood, children's)
  • manag* (managment, manager, managers) 

6. "...." (inverted commas) use for a phrase

  • "mental health"
  • "occupational therapy"

7. Wildcard ? will search for any single letter in the space. e.g. wom?n will search women, woman, organi?ation will search organisation, organization.

8. Wildcard * can also be used where alternate spelling may contain an extra character. e.g. p*ediatric, will search paediatric or pediatric, behavio*r, will search behaviour or behavior.


See SPH Library Search Filters for Various Databases Libguides for additional tips. 

Journal Databases

MEDLINE 1996 - present & In-process (Ovid) : MEDLINE provides authoritative medical information on medicine, nursing, dentistry, veterinary medicine, the health care system, pre-clinical sciences, and much more.This covers only 1996 forward but the great majority of SRs have been published since then.

PubMed: PubMed comprises more than 26 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites. PubMed is free, but by using this link you will have the best access to the full text of articles that you find. Medline and PubMed are nearly identical; the biggest difference is in HOW you search!

PsycINFO 1967 to present (Ovid): Contains citations and summaries of journal articles, book chapters, books, and technical reports in the field of psychology and psychological aspects of related disciplines including medicine, psychiatry, nursing, sociology, education, pharmacology, physiology, linguistics, anthropology, business, and law. If you are doing behavioral research, start with either Medline or PubMed, but PsycINFO is a must as it covers the psychological research. 

CINAHL Plus with Full Text : Covers nursing, biomedicine, alternative/complementary medicine, consumer health and 17 allied health disciplines. Can limit to systematic reviews by using the drop down menu next to Publication Type.

PubMed Clinical Queries: A specialized PubMed search interface that affords an easier, more focused access to clinical studies, systematic reviews and medical genetics information.

EMBASE is a comprehensive index to peer-reviewed biomedical literature with international scope, covering 1947-present. EMBASE indexes more than 2,700 journals not covered by PubMed/Medline and includes about 300,000 conference abstracts annually from 2009 to the present. EMBASE combines its own ontology, EMTREE, with that of Medline, so that more of the relevant search results are retrieved in a search. EMBASE is an ideal resource for preparing systematic reviews and tracking drug and medical device information. Supported: IE8, 9 and 10; latest versions of Firefox, Safari and Chrome; Windows XP, Vista and 7, and latest OS X version.E 

SAGE Research Methods Online was created to aid scientists, faculty members and students in the process of setting up and completing a research project, from formulating the fundamental question, to choosing appropriate research and analysis methodologies and design elements, to the presentation and dissemination of results. Geared primarily to those working in the social and health sciences, SAGE Research Methods Online combines a wide range of SAGE content-- books, journals, references (including the 'Little Green" and "Little Blue" books series) case studies, and video resources. Explore methods and concepts, gain in-depth understanding of particular methods, identify new methods, conduct research, and communicate your findings with the help of this resource. The user can also create and share personal methods lists.

The SCOPUS database contains millions of records from 10,150 life and health sciences publications (including all journals contained in Medline and EmBase) and includes most other sciences and humanities-- coverage of 20,450 journal titles. SCOPUS also indexes the proceedings of 750 conferences.  Searching also pullsl in relevant Web resources, organized under a separate tab. Another tab separates patent results from patent offices in the US and worldwide. SCOPUS provides a Journal Analyzer tool that graphs journals, singly or for comparison, from 1996 to present, showing total citations, number of articles published, total cites divided by number of articles, and the percentage of non-cited articles. Affiliation searching is also provided. A free login for authorized users provides additional advantages: a customizable personal profile for saving citation lists and tracking authors; a publication alert service; and direct export to RefWorks. For SCOPUS's tutorials, click here.  NOTE: Scopus may not support Safari and will cease to support IE7 in September 2014. From the website: "In order for our users to continue benefitting from Scopus’ new features and functionalities, we recommend that you upgrade your browser to IE 8 or higher or use Google Chrome or Firefox browsers."


Free Resources

There are several sites with systematic review databases.  Many of these are indexed in Medline/PubMed.  If you have not checked there first, do so!  Search these sites to make sure, especially PROSPERO as it is a registry of SR protocols.

Centre for Reviews & Dissemination (University of York)

  • PROSPERO: Registry of systematic review protocols.
  • Search CRD Database : This organization produces DARE (Database of Abstracts of Reviews of Effects) and provides content to the Cochrane Library. A search at this site (updated daily) draws evidence-based healthcare information from DARE, the National Health Service's Economic Evaluation Database (EED), and the Health Technology Assessment (HTA) database. CRD provides systematic reviews, economic evaluations and health technology assessments on your topic of interest. 
  • Canadian Health Technology Assessment

ClinicalTrials.govRegisters trials that are recruting and reports which have been completed.  It also has results for many studies.  Since a majority of the trials in this registry are never published, you'll need to search here if you're looking or clinical trial data.

WHO International Clinical Trials Registry Platform: This is a meta-site; multiple national registries meet the standards established by the WHO ICTRP (including  

Agency for Health Research & Quality


Documenting Search Results

You will need to keep track of:

  • Databases searched, including database provider/platform (eg. OVID Medline, ProQuest PsycINFO, Ebsco CINAHL)
  • Date search was conducted
  • Search strategy: subject headings and keywords used, including whether terms were exploded, truncated, and how terms were combined
    TIP!  Copy and past the search exactly as run and include in full, including numbers of records retrieved
  • Years searched
  • Filters used
  • Number of results retrieved for each search
  • Total number of records 
  • Duplicates identified
  • Numbers pre-screening and post-screening

In addition, all searches conducted via handsearching must identify the source (name of journal, conference proceedings, etc), plus the years.

Here is a very generic literature search tracking log  but other universities have developed templates to help with the documentation process:

PIECES Workbook Excel workbook designed to help conduct, document, and manage a systematic review. Made by Margaret J. Foster, MS, MPH, AHIP Systematic Reviews Coordinator Associate Professor Medical Sciences Library, Texas A&M University



PubMed by Year