Analysis 175 Enzymes 174 History 111 Mathematical models 51 History and criticism 43 Data processing 39 Mathematics 35 Addresses, essays, lectures 28 Politics and government 28 Psychology 27 Chemistry, Organic 24 Collected works 24 Criticism and interpretation 24 Research 24 Food 23 Methodology 23 Psychological aspects 23 Pollution 21 Polymers and polymerization 20 Synthesis 20 Children 19 Cognition 19 Economic conditions 19 Materials 19 Social aspects 19 Environmental aspects 18 Social conditions 18 Technique 18 Microbiology 17 Perception 17