Nursing 18,811 Nutrition 17,899 Nationalism 17,158 National security 16,711 Natural history 16,527 Navigation 11,623 Nuclear power plants 9,405 Natural resources 9,286 Neoplasms 8,691 Nobility 8,676 National parks and reserves 8,544 Nature 7,543 Navigation improvements 6,408 Nervous system 6,125 Natural gas 5,955 NATURE 5,898 Names, Geographical 5,884 Nurses 5,417 Nuclear energy 4,884 Nonprofit organizations 4,682 Newspapers 4,673 Nuclear weapons 4,628 Nuclear reactors 4,472 New business enterprises 4,471 National socialism 4,177 Neurology 4,102 Naval operations 3,937 Names, Personal 3,808 Narration (Rhetoric) 3,771 Nervous System Diseases 3,699 Nanotechnology 3,669 Numerical analysis 3,608 Nuclear nonproliferation 3,476 Neurosciences 3,365 Naval officers 3,343 Neuropsychology 3,277 Nuclear physics 3,096 Nature conservation 3,072 Nautical charts 3,059 Nuclear facilities 3,010 Number theory 2,859 Names 2,839 Nutritional Physiological Phenomena 2,832 Natural disasters 2,829 Numerical solutions 2,791 Nursery rhymes 2,772 National characteristics, American 2,752 Noise 2,744 Napoleonic Wars, 1800-1815 2,667 Nursing Care 2,663 Neural networks (Computer science) 2,615 Nanostructured materials 2,582 Nutritional aspects 2,447 Numismatics 2,409 Nuclear industry 2,302 Novelists, American 2,294 Non-governmental organizations 2,292 Nonfiction 2,254 Natural law 2,250 Navajo Indians 2,171 Nuclear warfare 2,147 Novelists, English 2,099 National banks (United States) 2,076 New products 2,043 Nuclear arms control 2,033 Natural theology 1,948 Nursing homes 1,896 Neutrality 1,856 Negotiation 1,813 Naturalists 1,778 Nature in literature 1,777 Nuns 1,773 Neurophysiology 1,758 Nuclear disarmament 1,756 Neoliberalism 1,738 Noirs ameĢricains 1,706 Nonlinear theories 1,679 Nationalisme 1,636 Nervous System 1,615 National 1,610 Naturalization 1,567 Naval art and science 1,391 Nationalists 1,386 Nutrition policy 1,371 Naval bases and depots 1,366 Nomenclature 1,357 NLU theses 1,328 Nuclear engineering 1,327 Naturwissenschaften 1,321 Newborn infants 1,319 Negers 1,310 Name 1,306 Nonviolence 1,300 Networking 1,277 Negotiable instruments 1,232 National income 1,220 Noise control 1,218 Neighborhoods 1,188 Natural gas pipelines 1,184 Nativity 1,181