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基于~(137)Cs技术的中国北方农牧交错带土壤侵蚀研究
作者: 姜洪涛   来源: 内蒙古师范大学 年份: 2010 文献类型 : 学位论文 关键词: 土壤侵蚀   农牧交错带   ~Cs   示踪  
描述: ttention, but also agriculture and eco-environmental sustainable development important problems. Farming-pastoral Transitional zone in north China, as our county returning farmland to forest and returning cropping land to grassland are the focus areas, natural environment and socio-economic conditions shown a clear transition characterized by the transition zone of the interpenetration and staggered distribution of agriculture and animal husbandry, which is curbing desertification important ecological barrier, but also ecologically fragile belts.
全文:样品,用美国ORTEC公司生产的型号为GMX50P4N型同轴型高纯锗γ探测器探测在不同土地利用方式下的土壤样品中的~(137)Cs含量,测得各土地利用类型中~(137)Cs含量从高到低的顺序为:草地
北方旱作农田水肥高效利用调控技术研究
作者: 于亚军   来源: 西北农林科技大学 年份: 2005 文献类型 : 学位论文 关键词: 水肥耦合   北方旱区   调控技术   WUE   技术规程  
描述: 长期以来,水分亏缺和肥力低下是制约我国北方旱作农田生产力水平提高的两大主要因素。因此,实施旱作农田水肥高效利用的合理调控,是实现旱作农区粮食高产稳产,提高农业生产效益,保证旱地农业可持续发展的重要途径。通过回顾世界旱作农区特别是我国北方旱作农田水肥调控技术的研究进展,综述了当前水肥调控技术研究的主要
全文:,以此指导旱作农田生产已是实现旱地农业可持续发展的迫切要求。 2 宁南水肥调控试验研究得到的主要结论 (1)降雨水年型谷子高产施肥技术 施肥对提高作物产量和水分利用效率(WUE)的效应存在阈值反应。春
元代地震灾害及赈灾体系述评
作者: 李彦鑫   来源: 吉林大学 年份: 2007 文献类型 : 学位论文 关键词: 缺陷   赈灾体系   元代   原因   地震灾害   赈灾权限  
描述: 元代(1271-1368)统治中国近百年,各种自然灾害的发生却不止百次,几乎年年有灾,年年多灾。地震是其中比较典型的自然灾害之一,虽然此时人们已经认识到地震有其自身原因,但具体原因是什么,并不是很清楚。因此当地震突然频繁发生的时候,元代从上至下,以往朝代积累起来的对地震灾害的认识逐渐被取代,开始动摇
全文:移民就粟、籴、减免租税和徭役等,但能行之有效的措施却是微乎其微的。元代所采取的赈灾措施与以往朝代没有太大的差别。其体察灾情的申检体覆制,存在很大缺陷,致使赈灾效果大打折扣。民间非官方赈灾应运而生
曹魏两大政治集团论析
作者: 王建明   来源: 山东大学 年份: 2009 文献类型 : 学位论文 关键词: 曹魏政治集团   汝颍   谯沛  
描述: Group headed by Cao Cao, Shuzhong Group led by Liu Bei, Jiangdong Group led by Sun Quan. The political bloc led by Cao Cao had the most abundant strength and talents came forth in large numbers. During the long-term expedition two major factions within formed: Ru一Ying Group and Qiao Pei Group. Ru-Ying Group charged civil service mainly and Qiao Pei Group was mainly made up of generals. These two groups had a long-term punitive expedition since Cao Cao fought against Dong Zhuo. Finally they unified vast areas of Northern China and carried out fruitful management, which avoided serious damage in the region by a long war and laid a good economic, political and military foundation for the unification of China in the future. Cao Cao fought against Dong Zhuo at the beginning, seizing Yanzhou, Zhangxiu, Xuhuai, Guandu, the four states, Wuhuan and Jingzhou, beat the seemingly invincible powerful opponents one after another. His forces got stronger and stronger. The two major political groups of Cao Wei supported Caocao on political and military aspects. Because these two groups represented the interests of their own, inevitably buried hidden dangers of can get on well with in adversity but can not share wealth. Ru-Ying Group is represented by the family of Han who was in the name of safeguarding the rule of the Eastern Han dynasty but to protect their interests. They can support Cao Cao's domination, but resolutely oppose his taking over Han dynasty. Qiao Pei Group on behalf of Cao Cao's family numbers who wished to gain greater benefits through Cao Cao's taking over Han dynasty. AD 209 years, The Battle of Red Cliff, which was Cao Cao's great cause of reunification of the most important ended in failure. As the highest strategic staff groups, Ru Ying Group throughout the campaign process simultaneously inconceivable aphasia, and the army of Cao Cao was defeated. Cao Cao became unable to dominate the country again in the rest of his life. This result was what Sun Quan, Liu Bei would like to see, Ru Ying Group was also willing to see it. From the historical records there was no record of staff at the Advanced Medium's death to give people the impression that Ru-Ying Group seemed to have known the defeat in advance. When Cao Cao was still alive, Qiao Pei Group holded the upper hand. But after the death of Cao Cao, Ru-Ying Group strongly supported Cao Pi to be the king. Finally Chen Qun put forward "Jiupinzhongzheng system", which established the family of Han's political monopoly. The two major political groups gradually moved towards a balance. After the death of Wei Ming King, the two major political groups split from co-operation, eventually formed a situation of endless immortality. Cao Shuang and He Yan of Qiao Pei Group were launched by Sima Yi through Gaopingling case when the situation was good. Sima Yi killed Cao Shuang and holded military and political power in the country. He cruelly blowed members of the Group Qiao Pei through a series of charges against them. Then, Jin Dynasty took place Wei. Ru-Ying Group obtained a comprehensive win. While Qiao Pei Group after its three generations with a heavy heart exit stage of history.
全文:战乱对这一地区的严重破坏,为日后中国的统一打下了良好的经济、政治和军事基础。 从曹操自伐董卓始,夺兖州、征张绣、徐淮、战官渡、定四州、征乌桓、占荆州,击败了一个又一个貌似强大不可战胜的对于,势力
陕西省农业现代化对农民增收的关系研究
作者: 雷婷   来源: 西北农林科技大学 年份: 2010 文献类型 : 学位论文 关键词: 陕西省   农民增收   农业现代化  
描述: e’ stability.This paper sets Shaanxi province as an example,hope to find the main factors affecting the income of peasants and their contribution in the system of the agricultural modernization, so as to identify the means of raising income of farmers from the view of the agricultural technology.
全文:农业现代化的发展水平。之后建立一个理论框架假定陕西农业现代化(以生产条件、投入水平、产出水平、科技水平为代表)对农民收入存在正的影响作用,再用这四类因子和农民收入的30年减数据建立科布·道格拉斯生产函数
元明清时期牛郎织女文学的传承与嬗变
作者: 周玉娴   来源: 首都师范大学 年份: 2009 文献类型 : 学位论文 关键词: 牛郎织女文学   传承嬗变   情节主题  
描述: 牵牛、织女是空中的两颗耀眼的星宿,也是原始星神崇拜的对象,后来这两颗明亮的星宿成为牛郎织女故事的主角,降落到人间,演变成了一个美丽的神话传说。从先秦到汉代,牵牛织女的神话传说一直在民间流传并得到发展和孳乳,到了魏晋南北朝时期,这个故事基本定型。张华的《博物志》和《殷芸小说》中,有这个故事的基本雏形。
全文:万历年间朱名世的《新刻全像牛郎织女传》、清代邹山的传奇《双星图》等都在故事原型的基础上孳生出的一些新作品。到了清代,宫廷和地方都要上演一些承应戏来庆祝,《昇署月令承应戏》中就有“七襄报章”、“仕女
敦煌俗字与宋本《玉篇》文字比较研究
作者: 井米兰   来源: 华东师范大学 年份: 2009 文献类型 : 学位论文 关键词: 比较   俗字   敦煌俗字   宋本《玉篇》   类型  
描述: gions and nationalities as it was discovered. As a result, an international learning has taken shape,that is the Study of Dunhuang, which contains the study of history, religion, culture, spoken and written languages, geography,ect. See from the angle of spoken and written languages,
全文:面貌。在这些写卷文书中,以汉文写卷为最多,而俗字的大量使用则是其最为显著的特点之一。 俗字相对于正字而言,不同时代亦有不同时代之俗字。敦煌俗字产生年代起于西晋延至北宋初年(咸五年),其中大部分俗字
阮籍隐逸思想研究
作者: 赵辉   来源: 河北师范大学 年份: 2009 文献类型 : 学位论文 关键词: 首阳山赋   隐逸   竹林七贤   阮籍   命世大贤  
描述: “竹林七贤”作为魏晋之际士人对阮籍、嵇康等七人品题的品目,其得名源于隐逸,其出现的直接契机是正始末年的竹林之游,在高平陵之变发生后,竹林之游受到士人瞩目和称道,“竹林七贤”之品目也在此时产生。随着政局、社会风尚和士人心态的继续推进,竹林七贤内部和整个士人阶层都在发生着变化,隐逸思想的转变是一个重要的
全文:道家的最早文本证据,其契机并非学界以往认同的高平陵之变,而是司马氏在嘉末年杀夏侯玄、擅行废立等一系列恶行。在此之后日渐险恶的局势使阮籍的隐逸思想发生了分化:一方面,在现实中他发挥庄子思想,用齐一
陕甘宁边区灾荒研究(1937—1947)
作者: 冯圣兵   来源: 华中师范大学 年份: 2001 文献类型 : 学位论文 关键词: 评价   救治   陕甘宁边区   灾荒  
描述: 本文按照《中国救荒史》的体例,运用丰富的第一手资料,在对陕甘宁边区前 十年间的灾荒概况、特点、成因和救治思想、救灾组织、救济工作程序以及救治措 施进行深入介绍和分析的基础上,借鉴灾害社会学的理论和比较的方法,对其救治 成效给予客观的评价。从而揭示中共领导边区渡过严重灾荒的主客观原因,并为现 实社会的
全文:又加重了自然灾害。 笔者以为,灾荒起因于人类和自然界之间的平衡、社会内部各要素之间的 衡、自然界内部各要素之间的平衡遭到破坏。从这个意义上讲,灾荒救治工作就是 重建这三大平衡。而且,只有同时实现这三
黄土高原北部农牧交错带庭院集雨提高水分转化效率技术途径的研究
作者: 马治国   来源: 中国农业大学 年份: 2005 文献类型 : 学位论文 关键词: 提高水分转化效率   黄土高原农牧交错带   集雨补灌   庭院经济  
描述: 本研究以内蒙古准格尔旗为例,研究了在半干旱气候条件下,建设集雨补灌农业.发展高效节水庭院经济的途径和对策。本区位于黄土高原北部农牧交错带,自然环境恶劣,水土流失严重,土壤生产力低下,由于过度开垦和放牧,植被破坏严重,生态恶化,急需治理。在此条件下,发展生态节水型庭院经济,可缓解生态压力,对于促进区域
全文:和放牧,植被破坏严重,生态恶化,急需治理。在此条件下,发展生态节水型庭院经济,可缓解生态压力,对于促进区域经济的发展具有重要意义。主要研究结果如下: (1) 在试验区,大力建设集雨设施是发展庭院经济的基础
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