Thema
Age Factors
2.858
North America
Americas
2.838
Journal Article
2.777
Population
2.719
Population Characteristics
2.711
Demographic Factors
2.705
Developed Countries
2.457
Northern America
2.372
United States
2.174
Youth
1.583
Population Dynamics
1.427
Research Methodology
1.425
Adolescents
1.238
Family Planning
1.138
Behavior
1.125
Developing Countries
1.079
Studies
956
Fertility
903
Economic Factors
865
Contraception
760
Research Report
735
Diseases
722
Socioeconomic Factors
667
Reproductive Behavior
652
Ethnic Groups
638
Adolescents, Female
625
Health
553
Education
542
Psychological Factors
542
Family And Household
531
Biology
528
Sex Behavior
519
Adolescent Pregnancy
509
Cultural Background
502
Socioeconomic Status
467
Family Characteristics
461
Organization And Administration
446
Latin America
432
Programs
416
Research Support, U.S. Gov't, P.H.S.
416
Research Support, Non-U.S. Gov't
409
Sampling Studies
382
Surveys
379
Reproduction
374
Contraceptive Methods
363
Contraceptive Usage
362
Comparative Studies
345
Delivery Of Health Care
344
Family Relationships
326
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