Journal Article 766 Behavior 267 Developing Countries 184 Population 164 Demographic Factors 159 Asia 124 Population Dynamics 119 mehr ... Economic Factors 117 Family Planning 111 Psychological Factors 100 Population Characteristics 90 Developed Countries 81 Health 79 Diseases 73 Research Methodology 73 Research Support, Non-U.S. Gov't 73 Americas 71 Fertility 71 Contraception 70 Organization And Administration 68 behavior 65 North America 63 Age Factors 62 Reproductive Behavior 62 Socioeconomic Factors 62 Programs 59 Education 57 Viral Diseases 55 Sex Behavior 51 Youth 51 weniger ...