Astrophysics 291 Astrophysics and Astroparticles Astronomy, Observations and Techniques 108 Astronomy—Observations 108 Observations, Astronomical 108 Astronomy 85 Space Sciences (including Extraterrestrial Physics, Space Exploration and Astronautics) 82 mer ... Space sciences 82 Astronomy, Astrophysics and Cosmology 72 Classical and Quantum Gravitation, Relativity Theory 54 Gravitation 54 Physics 46 Nuclear physics 34 Planetology 33 Quantum field theory 28 Cosmology 27 Elementary Particles, Quantum Field Theory 25 Elementary particles (Physics) 25 Plasma (Ionized gases) 24 Plasma Physics 24 Particle Acceleration and Detection, Beam Physics 23 Particle acceleration 23 Heavy ions 20 Nuclear Physics, Heavy Ions, Hadrons 20 Atoms 19 Particle and Nuclear Physics 19 Popular Science in Astronomy 19 Geophysics 17 Geophysics/Geodesy 16 Astrobiology 15 mindre ...