Subject
United States History
89
African Americans History
32
Sociology
28
U.S. states Politics and government
28
Political participation
23
Industrial revolution
13
International relations
13
United States Emigration and immigration History
13
World politics
13
War
12
Social institutions
11
America
10
Biography
10
Equality
9
Reconstruction (1939-1951)
9
World War, 1939-1945
9
Social change
8
Depressions
6
Ethnicity
6
Nineteen twenties
6
Racism
6
Reconstruction (U.S. history, 1865-1877)
6
World War, 1914-1918
6
Collective behavior
5
Political science
5
Social movements
5
Women's studies
5
Celebrities
4
Health
4
Indians of North America History
4
Asia
3
Astronomy
3
History, Modern
3
Home economics
3
Middle East
3
Nineteenth century
3
Nutrition surveys
3
Outer space Exploration
3
Physical sciences
3
Religion
3
Space flight
3
World history
3
Asian Americans History
2
Civics
2
Civil rights
2
Economics
2
Europe Civilization
2
Europe History
2
Families
2
Food
2
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