A.生產(chǎn)層次B.企業(yè)層次C.企業(yè)群落層次D.國(guó)民經(jīng)濟(jì)層次
(1)思想觀念障礙 (2)技術(shù)障礙; (3)資金和物質(zhì)障礙; (4)政策法規(guī)障礙