Bohr's work on the structure of atoms was awarded in 1922 with the Nobel Prize. After 1930, the activities within his Institute were increasingly focused on the constitution, transmutations, and disintegrations of atomic nuclei, and further developed an understanding of nuclear fission permitted by the "liquid droplet theory." These activities formed the basis for important theoretical investigations of nuclear physics that followed. Problems encountered with quantum physics were clarified through contributions to the field made by Bohr. In particular, Bohr developed the "concept of complimentarily," whereby he demonstrated how the scientific outlook of the general populace has been greatly affected by changes in the field of physics, and how the scope of atomic physics reaches throughout all facets of human knowledge.

Bohr escaped to Sweden during the Nazi occupation of...

At this time, he became associated with the Atomic Energy Project, and focused his efforts on the peaceful application of atomic physics. He held strong views regarding political problems that would arise from atomic weapon development. Bohr remained active in the field of physics with his involvement in many academies, commissions, and institutes. During his final years he showed interest in the emerging molecular biology field.
References

Niels Bohr - the Nobel Prize in Physics 1922." Nobel Lectures, Physics 1922-1941. Amsterdam: Elsevier Publishing Company, 1965. Retrieved 2/10/2007 at http://nobelprize.org/nobel_prizes/physics/laureates/1922/bohr-bio.html.

Thomsen, Dietrick E. "Going Bohr's Way in Physics - Niels Bohr's Centennial." Science News 11 January 1986.