When searching in library catalogs for materials related to social movements, there are a number of terms you can use that address different aspects of the broader subject. Using any one of the following in combination with other subject terms like "United States," "History," and "20th century" can usually yield good results:
Anti-environmentalism
Civil Rights
Civil rights movements
Environmental justice
Environmental protection
Environmentalists
Feminism
Fundamentalism
Gay activists
Gay liberation movement
Gay rights
Gay-straight alliances
Green movement
Immigrants - Political activity
Labor
Labor movement
Left-wing extremists
Minorities - Political activity
Nativism
New Left
Political activists
Political participation
Political persecution
Poor - Political activity
Protest movements
Radicalism
Right-wing extremists
Sexual minorities
Social action
Social movements
Social change
Social justice
Student movements
Students - Political activity
Tea Party movement
Tea Party Patriots
Welfare rights movement
White supremacy movements
Wise Use movement
Women in the labor movement
Women's rights
Working class
Youth - Political activity
Youth movements
