History 104 Karl Marx 51 Philosophy 45 Biography 35 History and criticism 35 Literature 33 Economics 30 Communism 28 Marxian economics 27 Research 27 Biotechnology 26 Marx, Karl 25 Marxism 25 Law and legislation 24 Intellectual property 20 Management 20 Sampling 20 Socialism 20 methods 20 Globalization 19 Human rights 19 Women 19 English literature 18 Molecular biology 17 Novel 17 Social aspects 17 American fiction 16 Criticism 16 Historiography 16 International relations 16