Nursing research is usually either "quantitative" or "qualitative." The first article below from the AORN journal describes these two different research genres. The sample articles below include both qualitative and quantitative studies.
Quantitative research: An experiment is conducted from which data are collected and quantified in some fashion, i.e. counted, analyzed numerically (e.g. effectiveness of a treatment).
Qualitative research: The data collected is more descriptive of people's beliefs, attitudes, etc. and is gathered through methods such as interviews and focus groups.