Evidence-Based Practice (EBP) guidelines are "systematically developed statements designed to help administrators, practitioners and patients make decisions about appropriate health care for specific circumstances" (Lim et al., 2008). Through a rigorous systematic review process, guidelines provide a synthesis of the literature on a specific topic and offer recommendations for tests, treatments, and many other aspects of clinical practice. They should not be used as fixed protocols, but rather are to be used in consideration along with the knowledge of a physician and the specific patient.
Lim, W., Arnold, D., Bachanova, V., Haspel, R., Rosovsky, R., Shustov, A., & Crowther, M. (2008). Evidence-based guidelines – An introduction. Hematology Am Soc Hematol Educ Program, 2008(1), 26-30. doi:10.1182/asheducation-2008.1.26
In addition to these resources, you may have access to additional subscription-based databases, such as UpToDate, through your healthcare employer. You may also find additional subject-specific guidelines from non-profit or professional organizations like the Oncology Nursing Society mentioned above.