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891.
The success of incorporating natural capital into resource- and land-use decisions hinges on the ability to quantify the ecosystem services, forecast the returns to the investments, convert these values into effective policy and finance mechanisms, and the presence of well-functioning institutions and infrastructure. However, ecosystem production functions i.e., the relationship between regulatory functions of the ecosystem and the economic activity it protects or supports are often poorly understood. Even with respect to Forest Watershed Services – a service that is widely recognized and even institutionalized through market based mechanisms in some parts of the world – the biophysical relationships between forests and services such as stream flow stabilization, water quality and water quantity are undefined, particularly for the tropics. For this reason, this study through time series data and multivariate analysis characterizes the relationships between Forest Cover (all lands with tree cover of a canopy density of 10% and above when projected vertically on the horizontal ground with minimum areal extent of 1 ha), water quality and cost of water treatment in the Western Ghats of peninsular India. In particular, the recursive relationship between the economic and environmental components is estimated by tracing the effects through the two-stage model. Annual value of impacts (increased ‘treatment cost’, increased ‘water losses due to backwash and desludging’, and changes in ‘water yield’) induced by loss of Forest Cover is estimated as 64.96 Indian rupee/m3 treated water/ha/year ($1.32/m3 treated water/ha/year). At an annual rate of change in the forest cover by −0.0088% (average annual rate of change in the forest cover between the years 1994–2007) the deforestation induced costs translate to 3.73 million Indian rupee/year ($0.075 million/year) according to the 2010–2011 prices for the Panjrapur treatment plant of the Municipal Corporation of Greater Mumbai. Thus, if deforestation is avoided the Municipal Corporation can save significant amount towards recurring costs of water treatment and to some extent mitigate the costs for the development of a new source.  相似文献   
892.
本研究采用色谱质谱(GC-MS)和色谱-同位素质谱(GC-IRMS)方法,对珠江口盆地Site4B沉积物中脂肪醇分子化合物分布以及单体碳同位素组成进行了研究。结果表明:长链脂肪醇碳优势指数(CPIC26—34:9.41—24.56)、平均碳链长度(ACLC26—34:28.85—29.99)以及n C26—n C30脂肪醇平均碳同位素组成(?29.13‰±0.87‰、?32.98‰±1.28‰和?32.73‰±1.61‰)均揭示了n C26—n C34脂肪醇属于陆源高等植物来源,n C16—n C20和n C24脂肪醇较正的碳同位素组成反映了化合物的海洋细菌来源,而n C22脂肪醇偏负的碳同位素特征(平均?33.26‰±1.51‰)反映了化学自养细菌来源。Site4B沉积物中的陆源输入主要来自南海周边河流,从12.7ka BP至今的沉积时期(0—80cm,文中深度均为埋深)和末次冰盛期(102—120cm),其陆源输入主要来自台湾岛河流,而在19.3—12.7ka BP沉积时期(80—102cm)和更新世沉积时期(120—300cm),台湾岛、吕宋岛和珠江口河流的陆源贡献普遍较低。Site4B沉积物中的海洋生产力主要来自海洋微生物输入的贡献,并主要受到海水温差影响;其中在35—150cm层位,海洋输入和南海暖流的强弱带来的海水温度的高低有关,而在150—300cm层位,则主要和冰期-间冰期的冷暖气候带来的海水温差有关。  相似文献   
893.
利用陆基实验围隔,采用原位培养法,对比研究5种草鱼(Ctenopharyngodon idellus)混养系统中细菌生产力的状况。结果表明,细菌生产力波动在(85.22±9.68)~(899.24±29.67)μg C·L-1·d-1,平均为(442.33±210.51)μg C·L-1·d-1。总体上,各处理组细菌生产力随时间呈现先升高后降低的趋势,在8月份达到最高值。其中,草鱼、鲢鱼和鲤鱼的三元混养模式中的细菌生产力显著高于其它处理组(P0.05)。细菌生产力总体上与水体初级生产力、溶解有机碳(DOC)和颗粒有机碳(POC)含量及水温均呈显著正相关,与水体磷酸盐含量呈显著负相关。通过主成分分析(PCA)发现,养殖前期水体无机氮(DIN)、DOC和POC含量对细菌生产力的贡献率高达44.058%,养殖中期DOC和POC含量对细菌生产力贡献率降为32.693%,而养殖后期DIN、DOC和POC含量对细菌生产力的贡献率为45.921%。研究表明,在养殖前期,DIN、DOC、POC是细菌生产力的关键因素;DOC、POC的重要作用使得养殖中期细菌生产力处在较高水平,但PO4-P含量成为限制因素;低温限制了浮游植物的初级生产力,使得养殖后期较高的营养元素含量只能维持细菌较低的生产力。  相似文献   
894.
This paper falls into the broad area of economic geography and economics of creativity,and it presents an alternative approach to explain why total factor productivity(TFP)growth is different across China′s regions.It establishes an empirical model to estimate the spatial agglomeration effects of creative industries on regional TFP growth,using China′s provincial panel data during the period of 2003 to 2010.We found that the creative industries agglomeration(CIA)has significant and positive impact on regional TFP growth.The result also implies that the CIA can facilitate regional TFP growth through promoting regional innovation instead of improving regional efficiency.Therefore,we argue that policy makers should take some measures to retain and establish more creative zones.  相似文献   
895.
文章基于MODIS下MOD17 A3、MCD12Q1产品,结合气温、降水数据,利用距平分析、趋势线分析以及相关分析等方法,对河南省2001年至2010年农田生产力的时空变化格局及影响因素进行了研究.结果表明:河南省农田生产力整体呈现东南高、西北低的态势;研究期内农田生产力呈现减少趋势的面积比例为4.98%,集中分布在信阳市的潢川县、固始县;河南省大部分农田的NPP与气温成正相关,成负相关的农田集中分布在西北边缘一带;农田NPP与降水成正相关的区域分布偏北,成负相关区域分布偏南,南阳盆地一带较为集中.  相似文献   
896.
利用试验数据校正并验证了机理性的作物生长模型WOFOST,随后模拟了华北42个站点1961—2006年夏玉米的光温和气候生产潜力。并首次运用新型统计检验聚类方法(CAST),对夏玉米光温及气候生产潜力的要素场分别进行了定量化分区。结果表明,华北夏玉米光温及气候生产潜力均分为5个不同荷载中心的区域。与农业气象传统等值线分区方法相比,将作物模型与CAST相结合进行的生产潜力区划可以更客观地反映以荷载中心台站为代表的产量的时空分布特征。这对于指导区域农业气候区划,实现区域农业可持续发展具有重要的理论及现实意义。  相似文献   
897.
Scientific study has generated a range of hypotheses about the ecological structure and function of seamounts. Interpretations of these ideas and data are vital to understanding how seamount communities will respond to anthropogenic impacts. Here, we examine how diversity and structure of seamount assemblages vary with depth and slope of the sea floor. We conducted ROV video transects on three seamounts of the Taney Seamount Chain in the Northeast Pacific Ocean. Depth and slope were both related to assemblage structure on the Taney seamounts. Depth differences were seen in alpha‐ and beta‐diversity but not density. Beta‐diversity and density but not alpha‐diversity varied with slope. Overall, slope and depth together explained 14–31% of beta‐diversity. The findings suggest that differences in beta‐diversity as related to depth gradients may differ among onshore and offshore and/or between shallow and deep summit seamounts. Specifically, we hypothesize that differences in productivity and depth gradients among seamounts may generate different patterns of beta‐diversity.  相似文献   
898.
Multiple hypotheses have emerged to explain the apparent paradox of high diversity of the deep‐sea benthos when the environmental conditions are often predicted to inhibit rather than promote diversity. Many fundamental facets of these paradigms remain incompletely understood despite being central to understanding how deep‐sea ecosystems, and more generally all ecosystems, function. Here, we examine nine major paradigms of deep‐sea diversity that deserve, in our opinion, a fresh research impetus. We purposely challenge many of these ideas to generate dialogue and encourage further research. Some of the axiomatic predictions of these paradigms are: (i) the deep sea is highly diverse; (ii) stable environments reduce competition; (iii) species have finely partitioned niches; (iv) biological cropping promotes diversity; (v) disturbance controls diversity; (vi) patch mosaics structure assemblages; (vii) productivity controls diversity; (viii) recovery from disturbance is slow; and (ix) the deep sea is notoriously under‐sampled. We critically examine the evidence for each of these predictions and highlight areas where knowledge gaps exist and linkages to general ecological theory should occur. We conclude each section with ideas about questions and hypotheses that may fruitfully be tackled in future projects.  相似文献   
899.
依据阿勒泰地区1961-2011年的逐月气象观测资料,采用目前常用的Thomthwaite Memorial模型计算了气候生产潜力.结果表明,阿勒泰地区的气候生产潜力为西部、北部最大,东部居中,南部的福海县最小,最大值与最小值相差达40%,空间分布不均;阿勒泰地区的气候生产潜力从20世纪60年代以来,总体呈现增加趋势,尤其是2000年以来,达到年代最大;阿勒泰地区气候生产潜力与年降水量有极好的正相关性,降水量是制约气候生产潜力的最主要的气候因子;气候生产潜力越大的县,变异系数越小,年变化越小,稳定性也就越好.  相似文献   
900.
Quantitative assessments of ecosystem service value (ESV) are of great significance for rational allocation of environmental resources and making regional ecological protection decisions. The method of equivalence factor per unit area is widely used for this purpose because of its simple algorithm. However, ESV is also affected by biotic and environmental factors (e.g., net ecosystem productivity (NEP) or precipitation), which are difficult to obtain at the regional scale, leading to uncertainty in ESV estimations. In this study, according to the equivalent factor modified by precipitation and NEP from four state-of-the-art process-based productivity models, i.e., CLM4.0, LPJDGVM, LPJGUESS and ORCHIDEE, we explored the temporal and spatial patterns of ESV of 15 administrative regions in northern China. The results show that the simulation accuracy of different models varied among four representative ecosystem types, i.e., typical steppe in northern China, alpine steppe in northwest China, farmland ecosystem in central China, and forest in northeast China, implying that model-based ESV estimates are ecosystem-specific. The ESV tends to decline from northeast to southwest in northern China. Regions with dense vegetation usually had high ESV due to better hydrological and thermal conditions. Low vegetation coverage areas, such as Qinghai and Xinjiang, had higher ESV because of their large geographical areas. The central and eastern developed regions without abundant natural resources had lower ESV due to their lower NEP. For different categories of ecosystem services, the regulation services (mainly water flow regulation services and climate regulation services) contributed the most to ESV. For the temporal dynamics, the total ESV of the 15 provinces, autonomous regions and municipalities showed an insignificant downward trend over the years. The regions with increasing trends of ESV were distributed in northwestern China, while pixels with decreasing trends of ESV were concentrated in northeastern China. Land use cover change may be the most important factor controlling the temporal dynamics of ESV. Our results can provide support for the enaction of reasonable strategies for ecological protection and economic development in northern China.  相似文献   
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