Strategies for Searching the Literature Using PubMed
Course Number: 340
Course Contents
Conducting a Traditional or Comprehensive Search and the Use of Filters
Without knowing about or using the MeSH or Advanced search features, the most common way of beginning a search is to type in the main search term, tooth erosion, on the Homepage (Figure 8).
Figure 8. Beginning a Traditional/Comprehensive Search.
Next click on Search to see the results, which result in finding 3483 citations (Figure 9a). To narrow these results to the most current and highest levels of evidence, use the filters that appear on the left-hand column.
Figure 9a. Results of a Traditional/Comprehensive Search.
Scanning down the column you have choices related to Text Availability, Article Type, Publication Dates, and Additional Features (Figure 9b).
Figure 9b. Customizing Article Types.
Clicking on Additional Features allows you to check off other Article Types, i.e., Practice Guideline and Comment, which are not a default publication type. Some of the other Additional Filters include Species, Languages, Sex, and Age (Figure 9c).
Figure 9c. Customizing Article Types (Continued).
By clicking on SHOW, it places Practice Guideline and Comment under Article Type (Figure 9d). If you had clicked on any of the options under any of the Additional Filters, they too would appear on the main page.
Figure 9d. Result of Adding Options under Article Types.
Of all the filters, perhaps the most important is Article Types since it allows you to search for studies by levels of evidence.
Beginning with clicking on Practice Guideline, the highest level of evidence, the 3483 citations are narrowed to 5 (Figure 10), which is much more reasonable to review. However, notice that the most recent one, #1, was published in 2008.
Figure 10. Using Filters to Narrow Citations to the Highest Level of Evidence, Practice Guideline.
If no Practice Guideline was identified or none of those found answer your question, then re-run the search. First clear the filter by clicking on “Clear all” to remove its selection. Next, click on Meta-Analysis, the next highest level of evidence. In this case, 12 citations are identified (Figure 11). Again, it’s important to only click on one filter at a time so that you know what level of evidence you have found.
Figure 11. Using Filters to Narrow Citations to the Highest Level of Evidence, Meta-Analysis.
If no Meta-Analysis is found, then re-run the search again by clicking on “Clear all” to remove Meta-Analysis and click on Systematic Reviews, the next highest level. There are 32 for this search. Continue this process so that you are able to identify the highest levels of evidence that answers your question. For a review of levels of evidence and the hierarchy that exists to guide clinical decision making see Evidence-Based Decision Making: Introduction and Formulating Good Clinical Questions.1
If there had been a large number of citations, another option is to use the “Publication Date” filter to limit the findings to the past 5 or 10 years. Also, if focusing on a specific age group, click on Show additional features and select the appropriate age group (Figure 12).
Figure 12. Additional Filters to Narrow Citations.