If you go to another EU country for research work, you must have comprehensive sickness insurance cover in your host country:
If you are a student, the European Health Insurance Card could be an option, if you are eligible. Make sure to apply for it with your home healthcare provider before you go.
If you are employed in the country you are conducting research work in, you will need to subscribe to a local healthcare scheme once there.
If you are being sent to a university or research institution in another EU country for a temporary period by your university or research institute of origin, then you will remain under your home healthcare scheme for the time you are posted. You should apply for the EHIC card, or for an S1 form, before leaving.