什麼是古典經濟學
英國經濟學派。18世紀後期由亞當斯密創立,到李嘉圖)和彌爾時臻於成熟。古典經濟學是最早涉及經濟成長動力的學説,反對重商主義學説,強調經濟自由,主要是自由放任主義和自由競爭的思想。其許多基本概念和原理是由亞當斯密在《國富論》(1776)中提出的,主張當人民依照私利行動時,國家所創造的財富是最大的。新古典經濟學家如馬歇爾表示供求量會分配經濟資源予最有效的使用。亞當斯密的思想被李嘉圖加以闡述和發展,強調在自由競爭條件下生產和銷售產品的價值(即價格)總是要同生產中所花費的勞動費用成正比。彌爾在《政治經濟學原理》(1848)中重新闡述了李嘉圖的一些理論,這一着作標誌着古典經濟學發展的高峯。後來有人修改古典經濟學學説而產生極為不同的結論,其中包括馬克思和凱因斯。
classical economics
School of economic thought largely centered in Britain that originated with Adam Smith and reached maturity in the works of David Ricardo and John Stuart Mill. The theories of the classical school were mainly concerned with the dynamics of economic growth. Reacting against mercantilism, classical economics emphasized economic freedom. It stressed ideas such as laissez-faire and free competition. Many of the fundamental principles of classical economics were set forth in Smith's Wealth of Nations (1776), in which he argued that a nation's wealth was greatest when its citizens followed their own self-interest. Neoclassical economists such as Alfred Marshall showed that the forces of supply and demand would ration economic resources to their most effective uses. Smith's ideas were elaborated and refined by Ricardo, who formulated the principle that the price of goods produced and sold under competitive conditions tends to be proportionate to the labor costs incurred in producing them. Mill's Principles of Political Economy (1848) gave the ideas greater currency by relating them to contemporary social conditions. Among those who have modified classical economics to reach very different conclusions are Karl Marx and John Maynard Keynes.
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什麼是電子計算機X射線斷層成像
一種醫學影像診斷技術。用X射線對人體投射,經檢測器測定透射後的放射量,通過電子計算機處理,重建出人體斷層圖像,並作出診斷。簡史1895年倫琴發現X射線後,X射線立即被應用於臨牀診斷。為了克服影像重疊的缺點,從1914年起,先後有人採用X射線管與膠片作同步反向運動的方...
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什麼是石膏
常用清熱瀉火藥。始載於《神農本草經》。別名細理石、寒水石、軟石膏。為硫酸鹽類礦物硬石膏族石膏。石膏有軟、硬石膏兩種,中醫中的石膏為軟石膏。產地和性狀石膏多產於海灣鹽湖和內陸湖泊形成的沉積巖中,常與石灰巖、黏土、巖鹽伴生。中國的主產地是湖北、安徽...
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什麼是皮內針
用於淺刺埋針的小型針具。因針僅刺入皮內,故名。按其形狀可分為顆粒式、環式、撳釘式三種:(1)顆粒式。形似毫針,長7毫米或9毫米,針尾為金屬顆粒,常用直徑為0.22毫米或0.26毫米的金、銀或不鏽鋼絲製成。(2)環式。針尾呈環狀,長7毫米或9毫米,常用直徑0.26毫米的不鏽鋼絲製成...
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什麼是熟地黃
常用補血藥。別名熟地。始載於《本草圖經》。為玄蔘科多年生草本植物地黃Rehmanniaglutinosa根經加黃酒拌蒸至內外色黑而油潤,或直接蒸至黑潤而成(圖1)。因其色黃,質量下沉,蒸熟曬乾入藥,故名。產地和性狀中國大部地區均有生產,主產於河南孟縣、温縣、武陟、博愛等...