Consider:
In addition to searching for research similar to your own, you will need to look for literature that mentions alternatives involving reduction, refinement, and replacement of animals in laboratory research.
Many people make the mistake of putting the term “alternatives” in the strategy and expect to find “all” possible alternatives. Because alternatives is a complex concept involving refinement, reduction and replacement, the use of “alternatives” as a search term is best used only in those areas of study where larger amounts of research have been conducted on alternatives, such as in toxicology or education. In other areas of research the term “alternatives” often retrieves results not related to the 3Rs.
See also suggestions from the Animal Welfare Information Center and the National Agricultural Library:
You need to combine your protocol specific keywords with relevant terms addressing reduction and refinement.
You need to combine your protocol specific keywords with relevant terms addressing replacement.