Marie Curie's major achievements in her scientific career include pioneering research in radioactivity, a term she coined, and becoming the first woman to win a Nobel Prize. She won the Nobel Prize in Physics in 1903 alongside her husband Pierre Curie and Henri Becquerel and later won a second Nobel in Chemistry in 1911 for her discovery of the elements polonium and radium. Her groundbreaking work not only advanced the field of physics and chemistry but also laid the foundation for advancements in medical treatments, particularly in radiation therapy.