什麼是弓箭
一種兵器,弓是一根用木頭或其他有彈性的材料製成的狹板,把它彎起來並用弦繃緊;箭是一根尾部帶羽毛的長木杆。把箭尾槽搭在弦上,然後向後拉箭,使弓產生足夠的張力,鬆開後,箭即被推出。弓的材料從木頭、骨頭、金屬到塑膠、纖維玻璃都有。箭頭是用石頭、骨頭和金屬製成。弓箭起源於史前時期。從古埃及時代到歐洲中世紀,在地中海一帶和歐洲,弓是首要的兵器,在中國和日本使用的時間則更長些。匈奴、突厥、蒙古人,以及歐亞草原其他民族在打仗時精於騎射,騎馬弓箭手是火藥未發明前戰爭中最為致命的武器。弩,一種複合型的弓,和英格蘭長弓使箭成為戰場上令人生畏的飛行兵器。土耳其弓的威力對中世紀後期的戰爭也有巨大影響。在許多民族的文明史上,弓在軍事上的重要性僅次於它作為狩獵器的價值。弓箭現在有時仍用在娛樂狩獵方面。亦請參閱archery。
bow and arrow
Weapon consisting of a strip of wood or other flexible material, bent and held in tension by a string. The arrow, a long wooden shaft with a pointed tip, is stabilized in flight by a feathered tail. The arrow is fitted to the string by a notch in the end of the shaft and is drawn back to produce tension in the bow, which propels the arrow when the string is released. Bow construction ranges from wood, bone, and metal to plastic and fiberglass; arrowheads have been made from stone, bone, and metal. The origins of the bow and arrow are prehistoric. The bow was a primary military weapon from Egyptian times through the Middle Ages in the Mediterranean world and Europe and even longer in China and Japan. The Huns, Turks, Mongols, and other peoples of the Eurasian steppes excelled in warfare as mounted archers; horse archers were the most deadly weapon system of pre-gunpowder warfare. The crossbow, the compound bow, and the English longbow made the arrow a formidable battlefield missile. The powerful Turkish bow had a great impact on warfare in the late Middle Ages. In many cultures, the bow's importance in warfare has been secondary to its value as a hunting weapon. It is still sometimes used for recreational hunting. See also archery.
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什麼是戈巴契夫
Gorbachev,Mikhail(Sergeyevich)蘇聯官員及最後一任總統(1990~1991)。1955年獲國立莫斯科大學法學學位,1980年成為中央委員會政治局正式委員,1985年被推選為蘇聯共產黨總書記。戈巴契夫開始對蘇聯的經濟和政治制度實施改革,但他的開放政策(glasnost)和重建政策(perestro...
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什麼是殘毒積累
有毒汙染物在人和生物體內殘留和蓄積的現象。在人和生物體內殘留和蓄積的有毒汙染物主要是金屬、農藥等。在中國部分地區所作的調查表明,在農作物、禽肉、蛋、茶葉、水產品中都有農藥殘毒(見農藥殘留)。如有機氯農藥DDT和六六六,在某些地區的農副產品中檢出率可達...
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什麼是聲望遠鏡
一種指向性很強的聲接收系統。將聲望遠鏡對準某方向來的聲波,這方向的聲波在望遠鏡上的響應最大,而其他方向來的聲波則相對較小。藉助於聲望遠鏡,可以求得聲源的空間分佈,能對一定範圍內的環境進行聲學分析,求出各個噪聲源的位置和強度,為防治噪聲汙染提供科學依據。...
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什麼是店肆
泛指各種商店,又有店鋪、鋪席、店、鋪、肆等名稱。沿革中國古代城市中的商店有兩大類:按行業分的專業商店和供應居民日常生活食用品的主副食、雜貨店。唐代以前的裡坊制城市中,前者集中於市,有專門官員管理;後者則在坊內沿街設定。宋代以後的街巷制城市中,專業商店演...