Classes 5+

5 NATURAL SCIENCES. MATHEMATICS. MEDICINE
50 NATURAL SCIENCES
50.1 Environmental protection. Nature conservation
50.11 Endangered species. Natural reserves
50.12 Air protection
50.13 Water protection
50.14 Soil protection
50.19 Animal protection
51 MATHEMATICS
51.1 Theory of numbers. Arithmetic. Algebra
51.2 Geometry
51.3 Analysis
51.4 Probability calculus
51.5 Special calculation methods
51.8 Mathematics as a hobby and pastime
52 ASTRONOMY. GEODESY
52.1 Theoretical astronomy. Celestial mechanics
52.2 Universe. Stars. Stellar systems
52.21 The solar system
52.3 Astronomical instruments
52.4 Space research. Space flights
52.6 Geodesy. Land surveying. Mapping
52.8 Chronology
53 PHYSICS
53.1 General and theoretical physics
53.11 Theory of relativity
53.12 Nuclear physics. Atomic physics. Molecular physics
53.13 Quantum theory. Quantum mechanics
53.3 Mechanics
53.4 Acoustics. Mechanical vibrations
53.5 Thermology
53.6 Optics. Radiology
53.66 Chromatics
53.7 Electricity. Magnetism
53.8 Physics as a hobby and pastime
54 CHEMISTRY
54.1 Theoretical and physical chemistry
54.2 Inorganic chemistry
54.3 Organic chemistry. Chemistry of plastics
54.4 Analytical chemistry
54.8 Chemistry as a hobby and pastime
55 PHYSICAL GEOGRAPHY. GEOLOGY
55.2 Geology. Geomorphology
55.3 Mineralogy. Petrology. Crystallography
55.4 Palaeontology
55.5 Meteorology. Climatology
55.6 Hydrology
56 BIOLOGY
56.1 Cytology. Cell biology
56.2 Biochemistry. Biophysics. Molecular biology
56.3 General microbiology
56.4 Genetics
56.41 Theory of evolution. Evolutionary biology
56.411 Biological anthropology
56.8 Nature handbooks
56.9 Ecology. Biogeography
57 BOTANY
57.1 Vascular plants
57.11 Trees. Bushes
57.3 Algae. Lichen. Fungi. Bryophytes
57.8 Plant anatomy. Plant physiology. Plant morphology
57.9 Plant ecology. Plant geography
58 ZOOLOGY
58.1 Vertebrates
58.11 Mammals
58.12 Birds
58.13 Reptiles. Amphibians
58.14 Fishes
58.2 Invertebrates
58.21 Insects
58.8 Animal anatomy. Animal physiology. Animal morphology
58.9 Animal ecology. Etology. Animal geography
59 MEDICINE. HEALTH CARE
59.1 Medical biology
59.11 Human anatomy
59.12 Human physiology
59.13 Medical microbiology. Immunology
59.2 General health care
59.21 Nursing science. Nursing work. Nursing staff
59.22 Care institutions
59.221 Hospital technology
59.23 Prevention of accidents. First aid
59.24 Social medicine. Environmental medicine
59.241 Occupational health. Student health. The work of a school nurse
59.27 Forensic medicine
59.28 Sports medicine
59.3 Personal health care
59.31 Beauty care. Looks
59.32 Baths. Sauna
59.33 Relaxation. Sleep. Insomnia
59.331 Yoga
59.34 Nutrition. Diets
59.35 Sexology
59.4 Methods of treatment
59.41 Physiotherapy. Physiological treatments
59.411 Acupuncture. Acupressure. Zone therapy
59.42 Aids and equipment for sick and disabled persons
59.43 Pharmacotherapy. Pharmacology
59.48 Surgery. Surgical treatment
59.49 Terminal care
59.5 Organs. Diseases
59.51 Infectious diseases
59.511 Venereal diseases
59.52 The skeleto-muscular system. Skeleto-muscular diseases
59.53 Viscera. Internal diseases
59.532 Respiratory organs. Respiratory diseases
59.533 Endocrinal glands. Metabolic diseases.
59.534 Blood. Blood diseases. The circulatory system. Diseases of the circulatory system
59.535 The digestive system. Diseases of the digestive system
59.536 Urinary organs. Diseases of the urinary system
59.54 Cancerous diseases
59.55 Nervous system. Neurology
59.56 Psychiatry
59.561 Mental health disorders
59.5612 Eating disorders
59.562 Psychotherapy. Mental health care
59.5622 Psychoanalysis
59.5623 Family, group and relational therapy
59.5624 Creativity and activity therapy
59.563 Mental health. Emotional disorders
59.564 Crisis psychology. Disaster psychology. Grief work
59.565 Suicides and their prevention
59.567 Use of intoxicants and stimulants
59.5671 Smoking
59.5672 Alcoholism. Alcohol use
59.5673 Narcotic addiction
59.57 Gynaecology
59.571 Pregnancy. Foetal development. Delivery
59.58 Allergies. Skin. Skin diseases
59.59 Sensory organs. Eye diseases. Ear, nose and throat diseases
59.6 Children's health care. Children's diseases
59.8 Health care for the elderly. Geriatric diseases
59.9 Odontology

59.31 Beauty care. Looks