With the rapid development of social economy,the strategic position of civil aviation in the national economy is highlighted,and its development potential is en
Firstly,current situation and main problems of science and technology development of soil and water conservation were analyzed,and then roles of science and tec
Since the founding of the New China in 1949,with the gradual development of the history and the constant change of the realistic situation,China's national
With the rapid development of urbanization,the pollution problem of rivers in cities and towns appears,which seriously affects life quality of residents around