The use of database limits is generally discouraged because most limits operate based on the indexing applied to individual records and use of them may compromise the sensitivity of the search. Custom search filters (hedges) created and tested for use in systematic reviews may be of value. The research units below have made their filters available Contact us for additional help locating or applying filters that do not use database limits (i.e., do not operate on database indexing).
Limit to Human Studies in PubMed
NOT ("Animals"[Mesh] NOT ("Animals"[Mesh] AND "Humans"[Mesh]))
Limit to Randomized Controlled Trials in PubMed
clinical[tiab] AND trial[tiab] OR "clinical trials as topic"[mesh] OR "clinical trial"[pt] OR random*[tiab] OR "random allocation"[mesh] OR "therapeutic use"[sh]