Philosophy 55 History 50 Education 34 Open source software 34 Social sciences 29 English fiction criticism-- Literature 26 History and criticism 26 Distance education 24 Computer science 23 English poetry criticism-- Literature 23 Sociology 22 Programmed instruction 21 Computer graphics 20 Distance Education 19 Social aspects 19 Women 18 Management 17 Methodology 17 Research 17 Economics 16 Social Sciences 16 Chemistry, Analytic 15 Literature 15 Open learning 15 Calculus 14 Mathematics 14 Globalization 13 Immune system 13 International relations 13 Mass media 13