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161.
从统计线性回归的角度对无味变换(unscented transformation,UT)进行分析,推导了迭代无味卡尔曼滤波(iterated unscented Kalman filter,IUKF)。针对IUKF计算量大的问题,结合弦线迭代法和IUKF,得到了一种新的混合迭代无味卡尔曼滤波器。数值仿真的结果表明,新滤波算法的精度优于扩展卡尔曼滤波、迭代扩展卡尔曼滤波和无味卡尔曼滤波,并可以有效降低IUKF的计算量。 相似文献
162.
影响莫高窟小气候的环境因子对比分析 总被引:2,自引:0,他引:2
应用不同时空尺度对莫高窟的小气候进行对比分析,发现莫高窟的地形地貌、水系统、植被等环境因子对其小气候有重要影响。莫高窟的小地形结构和水系统对其风速、湿度、太阳辐射等有显著影响。2005年4—12月窟前与窟顶月平均相比,太阳辐射总量降低411.21MJ/m^2,地表温度降低2.7℃,相对湿度增大9%,风速降低3.7m/s。窟前月较差小于戈壁0.9℃。但对于气温而言,主要受较大尺度因素的控制,窟前、窟顶、戈壁均处于同一温度层。2004年莫高窟日较差比敦煌小4.8℃。莫高窟的环境因子使莫高窟周边形成了更为稳定的小气候,非常有利于文物保护,这也是千年莫高窟保存至今的一个重要原因。 相似文献
163.
Guobin Fu Neil R. Viney Stephen P. Charles 《Theoretical and Applied Climatology》2010,99(1-2):229-238
This paper evaluates the various root transformations (2/3, 7/12, 1/2, 5/12, 1/3, and 1/4) of daily precipitation amounts fitted with a truncated normal distribution model for 189 stations across Australia. The results indicate that all stations used in this study can be identified to have a specific root transformation resulting in a “good” fit with a normal distribution and the minimum correlation coefficients (r) fitted with a normal distribution is 0.9925. The 5/12 power transformation leads to the “best” fit with a normal distribution in 47% of stations across Australia. This conclusion could extend the applications of many statistical testing techniques and methods on daily precipitation studies. 相似文献
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Sustainability was defined as the continuous support of human quality of life within a region’s ecological carrying capacity.
Ecological footprint was a quantitatively measuring indicator to analyze the sustainable use of natural resources and had
been widely used to evaluate whether the development of a certain region was within the range of the capacity of natural ecosystem.
In the present study, production data, consumption data and statistics communique of Zhifanggou watershed were analyzed to
determine per capita ecological footprint, biological carrying capacity and related indices. On the basis of theory a model
was applied that showed the biologically productive land area required by a defined population—ecological footprint model
before and after grain for green policy. Result showed that after introducing the grain for green policy, per capita ecological
footprint was reduced from 0.733 to 0.650 hm2 cap−1 and biological capacity was increased from 1.559 to 1.567 hm2 cap−1. There was a surplus of ecosystem resources both before and after the grain for green policy and this increased as a result
of the policy. The related ecological footprint indices analysis showed that 10,000 RMB of GDP of ecological footprint was
reduced, but ecological efficiency, ecological footprint index, bio-diversity of ecological footprint and system development
ability increased Results demonstrated that conditions in this watershed improved and development potential was enhanced.
Meanwhile, the sensitive index of forestland was strengthened more than other biological productive areas after introducing
the policy. In adjusting and improving the land use structure created a resource-saving mode, forming resource-saving increase
mode gradually, and triggering sustained consumption which will improve the ecological environment of zhifanggou watershed
in the future. 相似文献
168.
小流域生态经济系统可持续发展评价 --以东北低山丘陵区黑牛河小流域为例 总被引:24,自引:0,他引:24
以黑牛河小流域为例,在详细分析东北低山丘陵区小流域可持续发展现状的基础上,对该小流域的可持续发展状况进行定量评价:从效益显著性、资源与环境可支撑性和系统运行稳定性3个方面,选择31个因素作为参评因子,建立评价指标体系;采用精度较高的均方差法确定指标权重,以消除人为经验主观判断,提高评价的客观性和准确率;运用递阶多层次综合法建立二级层次指标(效益显著性、资源与环境可支撑性和系统运行稳定性)评价模型,多目标线性加权函数法建立流域系统综合评价模型,评判出了该区小流域的二级层次指标和综合指标的可持续发展水平,并有针对性的提出了小流域可持续发展的具体对策和建议。 相似文献
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