Advanced Search Builder and Search History Feature
Another valuable tool for conducting an evidence-based search is the Advanced Search Builder, including the Search History feature. This allows you to view all the search strategies that have been run and their results. It also allows you to combine previous search queries using the Boolean operators with new search queries. PubMed may move a search statement number to the top of the History when it’s used again, so the search queries may appear to be out of numerical order. Note when combining searches, the terms do not need to be spelled out again. Instead of typing out toothpaste AND stannous fluoride, just type the number of the search, e.g., #2 add with AND #3. Please note, you MUST use the # sign before the actual number.
Figure 7a. Search History on Advanced Search Builder Page.
Using the Advanced Search Builder, you can see that the terms toothpaste (#2) AND stannous fluoride (#3) were then combined (#4), which then was combined with tooth erosion OR erosive tooth wear (#1). This limited the number of citations found to 63 (#5). Next, a search for sodium fluoride and potassium nitrate (#6) identified 100 citations. It then was combined with #2 to limit the findings toothpaste. This resulted in 40 citations (#7). The final step was combining searches #5 AND #7 to identify studies that included both types of fluoride toothpaste and studies related to tooth erosion/erosive tooth wear in relation to tooth erosion (#8). This resulted in retrieving 4 studies. By clicking on 4 under the column Results, you can see the four studies (Figure 7b).
Figure 7b. Studies Identified Using Advanced Search Builder.
If none of these studies answers Nathan’s question, then the search needs to be expanded by using broader or more generic terms as mentioned earlier.
As you can see from this search, terms were searched individually prior to combining them. This allows the user to see exactly what results were obtained for each term. Skipping the search for individual terms prior to combining them can result in missing important citations.