TY - Acta Geographica Sinica A1 - Cheng MA, Xiaoyue WANG, Yaxin ZHANG, Shuangcheng LI T1 - Emergy analysis of ecosystem services supply and flow in Beijing ecological conservation area Y1 - 2017-06-25 00:00:00.0 JF - Acta Geographica Sinica JO - Acta Geographica Sinica SP - 974 EP - 985 VL - 72 IS - 6 UR - {https://www.geog.com.cn/EN/10.11821/dlxb201706003} N1 - 10.11821/dlxb201706003 ER -