id	keyword
essd-1188	urban
essd-1188	rural
essd-1188	development
essd-1188	agglomeration
essd-1188	connection
essd-1188	chongqing
essd-1188	units
essd-1188	area
essd-1188	ccua
essd-1188	equilibrium
essd-1188	integration
essd-1188	level
essd-1188	core
essd-1188	chengdu