On the initial page, before entering your search terms at the top, scroll down to the 'Limit Your Results' section and there are checkboxes you can select for 'Any Author is Nurse' and 'First Author is Nurse'.
Add "AND (nurs* [affil])" to your search string. This will limit your results to only those articles which have authors whose claimed work affiliation includes some form of the word 'nurse' (e.g., 'George Washington University School of Nursing').
A peer-reviewed journal is one in which articles are submitted to researchers who are experts in the field, who evaluate the content, research methodology, and references for accuracy before they are published.
Here are some ways to determine if an article is peer-reviewed:
Drug Information Portal: Gateway to selected drug information from the National Library of Medicine and other key government agencies.
Epocrates Essentials: Evidence-based resource providing disease and drug information
Lexicomp: Comprehensive clinical drug information
Natural Medicines: Provides information on dietary supplements, natural medicines, and complementary alternative and integrative therapies.