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121.
云南省玉溪市引种番茄椒的气象条件分析及对策研究 总被引:1,自引:0,他引:1
通过对云南省玉溪市2001~2004年引种番茄椒田间试验观测数据及当地同期气象资料的对比分析,结果表明云南省玉溪市可有选择性露地引种番茄椒,但需要安排好适宜的播种期和移植期才利于提高单位面积产量。这一结果对指导玉溪市引种、推广番茄椒品种有积极地参考作用。 相似文献
122.
There were 102 meso-α-scale convective systems(MαCSs)generated over China and the neighboring sea during June-August 1995.Those MαCSs were concentrated in three major areas:the west of South China,Sichuan Basin,and the middle and lower reaches of the Changjiang and the Huanghe River Basin.Six cases of MαCS in different regions are given to show the variety of the MαCS genesis and development by the distributions of their cold-cloud-shield black body temperature. 相似文献
123.
124.
《自然地理学》2013,34(6):507-530
The advance of saltcedar from the American southwest to Montana between the mid-19th and mid-20th centuries crossed the Continental Divide—a major topographic and climatic barrier to natural dispersal by southern plants. Interviews, archival information, and field observations are used to explain this advance. According to archival documents, saltcedar was planted in communities adjacent to the Bighorn River in central Wyoming as part of urban beautification projects in 1936. Bureau of Reclamation reports describe tree plantings for erosion control between 1940 and 1953 within the Riverton Irrigation Project in the Wind-Bighorn River watershed. These introductions were followed by rapid natural dispersal northward by water and wind through the Wind/Bighorn system and into the Yellowstone and Missouri rivers in Montana before closure of Boysen and Bighorn dams in 1951 and 1967. Construction equipment and ornamental plantings further transported saltcedar to the Fort Peck Reservoir and the Musselshell River. We conclude that, without control at its advancing fronts, a complete ban of its sale, and removal of existing ornamental and erosion control trees, saltcedar will invade most suitable sites in the Missouri watershed and disperse northwards into western Canada. 相似文献
125.
本文根据地理纬度、经度和海拔建立了吉林省东部长白山区热量资源的推算方程;采用地理细网格场的分析方法,推算出山区各地的热量资源状况,绘出细网格热量资源分布图,并以此为依据,制定了该山区农作物品种布局方案。 相似文献
126.
雅鲁藏布江断裂带附近地应力场的变化特征 总被引:4,自引:1,他引:3
为了解雅鲁藏布江断裂带附近的原地应力场状态,采目前先进的水压致裂方法,在西藏拉贡机场CK3号井中进行了52.5~73.6m、92.2~105m、117.12~142.6m、142.91~153.7m、187.38~173.7m、187.38~217.98m、227.3~288m、293.5~322m共计八个深度段的地应力测量。运用工程地质分析原理和统计分析方法对研究区地应力场的总体变化特征以及垂直埋深、水平埋深的关系进行了分析研究,取得各测段处的最大、最小水平主压应力的量值以及岩石的原地抗张强度、岩石的重张压力等力学参数。另外利用区域地质构造和三维有限元分析方法相结合的技术,分析确定测区附近的主应力方向,为雅鲁藏布江构造带的应力场研究和工程设计提供依据。 相似文献
127.
LOU Angang) )* HU Yuebo) KUANG Liang) ZHANG Xueqing) DU Peng) )) College of Environmental Science Engineering Ocean University of China Qingdao P. R. China ) Key Lab of Marine Environmental Science Ecology P. R. China 《中国海洋大学学报(英文版)》2009,8(1)
The 3-D ECOMSED ocean model was applied to establish a time-dependent boundary model for Jiaozhou Bay (JZB), in which the operator-splitting technique was used and the ‘dry and wet’ method was introduced. The influence caused by JZB reclamation on the surface level, residual currents, tidal system and tidal energy of M2 tidal system were predicted and analyzed. The results show that JZB reclamation has slight impact on the M2 tidal system, in which the variation of amplitude and phase is less than 1%.The ch... 相似文献
128.
Typical Structure, Variety, and Multi-Scale Characteristics of Meiyu Front 总被引:1,自引:0,他引:1 下载免费PDF全文
Meiyu front plays an important role in summer rainfall in central China. Based on the GMS-5 satellite images, NCEP reanalyses (2.5°×2.5°) and final analyses (1°×1°) data, and meteorological conventional sounding observations, the horizontal and vertical structures of the Meiyu front were summarized using multiple diagnostic variables, including winds, temperature, jet stream, front, pseduo-equivalent potential temperature, divergence, vertical motion, static instability, etc. In this paper, four cases were selected and analyzed, two of which are in 26-28 June and 23 July 2002 during the Experiment on Heavy Rain in the Meiyu period in the lower reaches of the Yangtze River, and the others are in May and July 1998. The two cases in July 1998 and July 2002 are the secondary Meiyu front cases. The results show that the structures and characteristics of the Meiyu front are different for various cases, or at various places and time, or at various stages of one case, and the frontal characteristics can be converted from the polar front to the equatorial front. Because of the interaction of the different scale circulations in the high and low latitudes, the horizontal structure of the Meiyu front has various forms.
The results in this paper also show that the typical Meiyu front consists of a narrow band with a high gradient of potential equivalent temperature below 500 hPa, south of which is warm and moist air mass, and north of which is the transformed air mass from the midlatitude ocean or polar continent. Below the mid troposphere, south of the front blows southwesterlies, while north blows easterlies. The ascending motion and precipitation usually occur ahead of the Meiyu front. In the upper troposphere, the subtropical front is above the Meiyu front, but two fronts are separated. In addition, the upper westerly jet stream and the easterlies to the south of the Meiyu front result in the upper divergent flow field.
The multi-scale characteristics of the horizontal structure of the Meiyu front can 相似文献
The results in this paper also show that the typical Meiyu front consists of a narrow band with a high gradient of potential equivalent temperature below 500 hPa, south of which is warm and moist air mass, and north of which is the transformed air mass from the midlatitude ocean or polar continent. Below the mid troposphere, south of the front blows southwesterlies, while north blows easterlies. The ascending motion and precipitation usually occur ahead of the Meiyu front. In the upper troposphere, the subtropical front is above the Meiyu front, but two fronts are separated. In addition, the upper westerly jet stream and the easterlies to the south of the Meiyu front result in the upper divergent flow field.
The multi-scale characteristics of the horizontal structure of the Meiyu front can 相似文献
129.
通过分析1997-2003年5-10月广西电网电力负荷月、周和节假日的变化特征,及与气温的相关关系,发现:电力负荷基本呈逐年增加的趋势,工作日和非工作日有着不同的变化特征,电力负荷与气温有明显的相关关系。采用逐步回归方法,建立了广西电网逐日电力负荷预测模型,对2002-2003年模型的拟合结果及2004-2005年模型的预测结果分析表明:模型对广西逐日电力负荷具有较好的拟合和预测效果,对逐日电力负荷的季节变化具有较好的拟合效果,尤其是夏季预测与实况趋势基本吻合。 相似文献
130.
佛山市产业专业化、多样化与经济韧性的关系研究 总被引:4,自引:1,他引:4
以2008年和2013年佛山市30个专业镇的数据为基础,分析其在经济冲击抵抗期的经济韧性。分析结果显示,佛山市专业镇在经济危机之后整体经济韧性恢复缓慢,专业化和相关多样化产业的发展不再有助于经济韧性的提升,而非相关多样化则相反。传统专业化的集聚优势式微,以低水平劳动密集型产业为主的专业化易于导致经济的脆弱性;相关多样化因技术含量低和协作关系弱的限制也无法发挥作用,虽然地方政府采取积极干预的手段,但效果并不明显;非相关多样化的发展则有利于培育新的产业结构,弥补受危机影响而流失的劳动力,维持地区的经济韧性。与既往研究相比,研究结果同样支持高度专业化区域经济脆弱性更大、稳健性更低的主流观点,但是传统观点一是多侧重于某个视角,并未将专业化与多样化进行对比分析;二是在多样化研究中并不区分相关多样化和非相关多样化的对经济韧性作用。结论认为,在专业镇持续转型的背景下,发展相关多样化产业不利于提高其经济韧性,而非相关多样化产业则是积极有利的,应该予以大力鼓励。专业镇作为珠三角经济发展的成功经验,其传统发展模式正面临着严峻的挑战,应积极探索建立新的多样化发展模式。 相似文献