History 35 Working class 16 Labor unions 14 Agriculture 11 Economic aspects 11 Peasants 11 Social conditions 10 更多 ... Petroleum industry and trade 8 Economic conditions 7 Employment 7 Labor movement 7 Women 7 Womyn 7 Economic development 6 Land tenure 6 Statistics 6 Management 5 Periodicals 5 Government policy 4 Politics and government 4 Social security 4 Division of labor 3 Economic policy 3 Employees 3 Environmental policy 3 Gas industry 3 Industrial relations 3 Privatization 3 Social aspects 3 Strikes and lockouts 3 少 ...