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101.
102.
Few studies of land use change were particularly considered the hierarchical data structure originating from different scales
and levels. Using interviewing data collected from 107 villages, 1,050 households and 4,780 fields between November 2003 and
August 2005, the objective of this paper is to predict the occurrence of land use from field to village level in mountainous
area, China, and to improve our understanding of the causes of land use. Household’s behavior in the choice of land use type
is guided by multiple, often confiding, household objectives, subject to the available resources, possible productive activities,
and external economic and biophysical constraints. For rice model, the household level variables cannot be substituted by
village level aggregates. Aggregated variables at village level do not capture any of the variability at the household level.
Village level variables can virtually be explained in virtue of the variables of field and household level. The households
and the villages show significant clustering of the occurrence of rice, and they explain the 11.3 and 4.5% variance, respectively.
For corn model, corn as dependent variable does not show any significant variance component. The variables of household and
village level have lower effects on the occurrence of corn. There is a significant relation between slope of a field and the
choice to cultivate corn and a significant random effect at the village level. However, cropland size, input–output, transportation
cost, even family income in household level and road density and food market development in village level, at some extent,
are controlled by slope. These variables do not influence corn cultivation significantly and that those are predominantly
determined by slope. In a word, the household level can be crucial in explaining land use at the field level. Multilevel analysis
can be applied to statistically model the occurrence of land use, and to explore a number of cross-scale propositions.
An erratum to this article can be found at 相似文献
103.
104.
As a part of Jordan’s efforts to quantify the effect of the Dead Sea level decline on the precious groundwater resources of the surrounding aquifers, the authors analyzed the historic or predevelopment inflows and outflows of the Dead Sea basin and the resulting water balance which included precipitation, evaporation, surface‐ and groundwaters. The predevelopment situation was taken as the point of departure for the sake of this study. Furthermore, the present situation was analyzed in an attempt to quantify the groundwater inflows into the Dead Sea as a result of drop in the Dead Sea level. The groundwater component and the corresponding saltwater/freshwater interface were taken as the variables to balance the levels of the sea that would have been reached without the contribution of the uncontrolled groundwater inflows as a result of the salt/freshwater interface seaward migration. The present day water balance that includes all the water diversion projects from all riparians indicates serious declines in the Dead Sea level. The effects of the present day level declines on the fresh groundwater/saltwater interface indicate that considerable amounts of groundwater are driven into the Sea as a result of the seaward migration of the freshwater/saline water interface. 相似文献
105.
In this paper the reaction of the salt‐/freshwater interface due to the changes in the Dead Sea level are elaborated at in details by using the inflows into the Dead Sea, the outflows due to evaporation losses and artificial discharges, and the hydrographic registrations of the Dead Sea level. The analyses show that the interface seaward migration resulted in a groundwater discharge of around 423 Mio m3 per meter drop in the level of the Dead Sea in the period 1994–1998 and of around 525 Mio m3/m in the period 1930–1937. The additional amount of groundwater joining the Dead Sea due to the interface seaward migration was 51 Mio m3 per one square kilometer of shrinkage in the area of the Dead Sea in the period 1930–1937 and 91 Mio m3/km2 in the period 1994–1998. The riparian states of the Dead Sea are nowadays loosing 370 Mio m3/a of freshwater to the Dead Sea through the interface readjustment mechanisms as a result of their over exploitation of waters which formerly fed the Dead Sea. 相似文献
106.
天津地区咸水井映震能力评估 总被引:2,自引:0,他引:2
系统处理了1992年以来天津地区4口咸水井的水位观测资料,使用R值对这4口井的映震效能进行了评估。认为:①这4口井的R值不高,主要原因是咸水层观测井水位异常时间较长,致使预报占用时间较长;②咸水层观测井水位异常幅度比较明显,异常性质的规律性较强,出现异常时易于识别;③咸水层观测井水位有异常有地震的比率达到了70%以上,这对有震的判定非常有意义。 相似文献
107.
108.
本文从硬件与软件两方面论述了SD智能数显仪与个人计算机之间的串行通信原理,并简述了其在工业自动化领域集散控制系统中的应用 相似文献
109.
110.
利用高空、地面形势场和物理量场等气象资料,对2011年2月26日锡林郭勒盟地区出现的大雪天气过程诊断分析。结果表明:这次大雪是在稳定的行星尺度天气系统作用下,受低空切变线配合河套气旋影响,满足了高低空急流耦合提供的动力抬升、低空急流建立的水汽输送及辐合、低层暖湿气流产生的能量不稳定等条件下产生的,属弱冷空气类槽涡型;西南涡(槽)和华北脊对大雪的产生和落区起到重要的决定作用,低层强盛的暖湿气团为不稳定能量的产生提供了条件;通过分析、总结,结合实际预报经验,提出了预报要点和指标。 相似文献