Many databases provide system based limits. Adding a limit to a search will exclude certain material not relevant to your research question, and therefore reduce the number of results. These functions vary from database to database but often appear on your initial search screen or beside your search results.
Examples include:
- limiting to English language
- limiting by publication date
- limiting to a specific document type
- limiting your search to specific fields, such as only searching in the Title/Abstract fields
The use of limits can result in the exclusion of relevant studies, so any use should be justified by the focus of your research and any constraints.
If conducting a systematic review for publication, always use a Search Filter in place of limits.