什麼是元朝
Yuan dynasty,亦拼作 Yüan dynasty,或稱為蒙古王朝(Mongol dynasty)。
蒙古遊牧民族在中國開創的朝代。成吉思汗於1215年進佔中國北方,但直到1279年,忽必烈汗才控有中國南部。蒙古人在北京建立首都(當時稱為大都)。他們重建大運河,其道路與郵驛站也維護良好。宋朝時還流通有限的紙幣,在蒙古帝國時則已全國通用。天文學、醫學和數學都有所進展;從東歐平原橫跨大草原到蒙古、中國的蒙古帝國,貿易暢通。許多外國人(以馬可孛羅最為着名)前往中國,也有許多中國人前往伊朗(Iran)和俄羅斯(Russia)遊歷,甚至遠達西歐。中國憎惡蒙古征服者,因為蒙古的管轄體制對中國人採取不利的差別待遇(參閲Kublai Khan)。中國的藝術家則藉由隱退與轉而表達自我,顯示消極的抵抗。文人畫廣受歡迎;小説有所發展,也出現新的戲劇形式。自1300年起,蒙古人中對繼承權的爭奪,削弱了中央政府;經常爆發的叛亂,多半與如紅巾的祕密會社互相聯絡。元朝於1368年被日後的明太祖所推翻。亦請參閲Ming dynasty。
1206~1368年
Yuan dynasty
orMongol dynastyDynasty established in China by Mongol nomads. Genghis Khan occupied northern China in 1215, but not until 1279 did Kublai Khan take control of southern China. The Mongols established their capital at Beijing (then called Dadu). They rebuilt the Grand Canal and put the roads and postal stations in good order. Paper money, which had had limited circulation under the Song, came to be used throughout the empire. Advances were made in astronomy, medicine, and mathematics, and trade was carried out throughout the Mongol empire from the plains of eastern Europe across the steppes to Mongolia and China. Many foreigners came to China (notably Marco Polo) and many Chinese traveled to Iran, Russia, and even western Europe. The Chinese resented the Mongol conquerors, whose governmental system discriminated against them (see Kublai Khan). Chinese artists demonstrated passive resistance by withdrawing and turning to personal expression. Literati painting became very popular; the novel developed, and new dramatic forms also appeared. Disputes over succession weakened the central government from 1300 on, and rebellions were frequent, many connected with secret societies such as the Red Turbans. The dynasty was overthrown in 1368 by the future Hongwu emperor. See also Ming dynasty.
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什麼是酶催化劑
即指酶,一類由生物體產生的具有高效和專一催化功能的蛋白質。酶催化劑和活細胞催化劑均可稱為生物催化劑。在生物體內,酶參與催化幾乎所有的物質轉化過程,與生命活動有密切關係;在體外,也可作為催化劑進行工業生產。酶有很高的催化效率,在温和條件下(室温、常壓、中性...
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什麼是時行感冒
感受時行病毒所引起的急性呼吸道傳染性疾病。西醫學稱為流行性感冒。全身症狀明顯,臨牀以突然惡寒、發熱、頭痛、全身痠痛為主要特徵。一年四季均可發生,冬春兩季較為多見。起病急驟,傳播迅速,傳染性強,常可引起大流行。時行感冒的病因多與氣候突變、寒温失常有關,如...
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什麼是激素
由內分泌細胞合成和分泌的、能將一定的化學信息傳遞到靶細胞併產生生物效應的微量化學物質。過去人們認為,激素是由體內無導管的內分泌腺體產生並直接分泌進入血液循環,轉運到遠處的靶器官發揮一定的生理作用。現已知激素的產生不限於傳統的內分泌腺體,激素的轉運...
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什麼是環境污染
自然的或人為的原因使某些化學的、物理的、生物的有害因素帶入人類賴以生存的空氣、水、土壤和食物等環境中的現象。人的生活環境中有着各種污染源,污染物質從各種污染源排出,通過人的呼吸、飲食,使人體健康和精神狀態受到直接或間接的、近期和遠期的(遺傳的)不利影...