If you hold the European Union Health Insurance Card (EHIC) you will be covered while your stay is temporary (as decided by the insurer in your home country). If your stay is not temporary (or if you have a job) you must have a Basic Dutch Health Insurance Policy.
This EHIC card is issued by Public Health Insurers in countries of the European Economic Area. Apply for the EHIC in your own country with your public health insurance provider or relevant social security authority.