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951.
Assessment of vulnerability for natural ecosystem to climate change is a hot topic in climate change and ecology, and will support adapting and mitigating climate change. In this study, LPJ model modified according to features of China's natural ecosystems was employed to simulate ecosystem dynamics under A2, B2 and A1B scenarios. Vulnerability of natural ecosystem to climate change was assessed according to the vulnerability assessment model. Based on eco-geographical regions, vulnerability of natural ecosystem to climate change was analyzed. Results suggest that vulnerability for China's natural ecosystems would strengthen in the east and weaken in the west, but the pattern of ecosystem vulnerability would not be altered by climate change, which rises from southeast to northeast gradually. Increase in ecosystem vulnerable degree would mainly concentrate in temperate humid/sub-humid region and warm temperate humid/sub-humid region. Decrease in ecosystem vulnerable degree may emerge in northwestern arid region and Qinghai-Tibet Plateau region. In the near-term scale, natural ecosystem in China would be slightly affected by climate change. However, in mid-term and long-term scales, there would be severely adverse effect, particularly in the east with better water and thermal condition.  相似文献   
952.
利用黄河源区1977-2006年土地覆盖数据集,分析了土地利用覆盖变化格局。根据高寒草地生态系统的特点,改进了生态功能服务价值系数计算方法,把土地利用的生态效益转化为简单易懂的货币形式,为决策者提供直观的生态信息。同时利用基于案例推理的CA模型模拟黄河源区2018年的土地覆盖情景,并得到其生态服务价值。研究表明:1977-2006年生态系统服务价值由460亿元降至418亿元,其中林地、高覆盖草地与湿地的生态服务价值分别减少10亿元、30亿元和20亿元,中、低覆盖草地生态服务价值提高20亿元,水体与沙(裸)地等变化不大。2006-2018年草地覆盖度将逐步上升,高、中覆盖度草地面积逐渐扩大,低覆盖度草地面积减小,生态服务价值得到较大幅度提升。  相似文献   
953.
Climate and land-use changes are projected to threaten biodiversity over this century. However, few studies have considered the spatial and temporal overlap of these threats to evaluate how ongoing land-use change could affect species ranges projected to shift outside conservation areas. We evaluated climate change and urban development effects on vegetation distribution in the Southwest ecoregion, California Floristic Province, USA. We also evaluated how well a conservation network protects suitable habitat for rare plant species under these change projections and identified primary sources of uncertainty. We used consensus-based maps from three species distribution models (SDMs) to project current and future suitable habitat for 19 species representing different functional types (defined by fire-response – obligate seeders, resprouting shrubs – and life forms – herbs, subshrubs), and range sizes (large/common, small/rare). We used one spatially explicit urban growth projection; two climate models, emission scenarios, and probability thresholds applied to SDMs; and high-resolution (90 m) environmental data. We projected that suitable habitat could disappear for 4 species and decrease for 15 by 2080. Averaged centroids of suitable habitat (all species) were projected to shift tens (up to hundreds) of kilometers. Herbs showed a small-projected response to climate change, while obligate seeders could suffer the greatest losses. Several rare species could lose suitable habitat inside conservation areas while increasing area outside. We concluded that (i) climate change is more important than urban development for vegetation habitat loss in this ecoregion through 2080 due to diminishing amounts of undeveloped private land in this region; (ii) the existing conservation plan, while extensive, may be inadequate to protect plant diversity under projected patterns of climate change and urban development, (iii) regional assessments of the dynamics of the drivers of biodiversity change based on high-resolution environmental data and consensus predictive mapping, such as this study, are necessary to identify the species expected to be the most vulnerable and to meaningfully inform regional-scale conservation.  相似文献   
954.
The Mediterranean coralligenous substratum is a hard bottom of biogenic origin, mainly composed of calcareous algae, growing in dim light conditions. Sponges are among of the most representative taxa of the coralligenous assemblages, with more than 300 recorded species of different habits: massive, erect, boring and insinuating. When sponges die, their siliceous spicules remain trapped in the biogenic concretion, offering the opportunity to describe the coralligenous spongofauna over a very long span of time, virtually dating back to a large part of the Holocene period. The data reported here were obtained from core samples collected from four coralligenous concretions. Each block was collected in a different locality of the Ligurian Sea: Santo Stefano Shoals, Bogliasco, Punta del Faro (Portofino Promontory) and Punta Manara. Radiocarbon age determinations indicate for these conglomerates a maximal age between 1600 and 3100 years. The spicules trapped in the cores show deep dissolution marks in the form of circular holes on their surface or present an enlargement of the axial canal. However, their original shape, generally intact, suggests the absence of mechanical injuries and allows a tentative identification at the species level. The analysis of these old spicules reveals an ancient sponge assemblage composed of 30 recognisable species. This indicates that almost one half of the sponge community today settled on coralligenous substrata has been present in the conglomerates for their entire existence.  相似文献   
955.
Sustainable development depends on maintaining ecosystem services which are concentrated in coastal marine and estuarine ecosystems. Analyses of the science needed to manage human uses of ecosystem services have concentrated on terrestrial ecosystems. Our focus is on the provision of multidisciplinary data needed to inform adaptive, ecosystem-based approaches (EBAs) for maintaining coastal ecosystem services based on comparative ecosystem analyses. Key indicators of pressures on coastal ecosystems, ecosystem states and the impacts of changes in states on services are identified for monitoring and analysis at a global coastal network of sentinel sites nested in the ocean-climate observing system. Biodiversity is targeted as the “master” indicator because of its importance to a broad spectrum of services. Ultimately, successful implementation of EBAs will depend on establishing integrated, holistic approaches to ocean governance that oversee the development of integrated, operational ocean observing systems based on the data and information requirements specified by a broad spectrum of stakeholders for sustainable development. Sustained engagement of such a spectrum of stakeholders on a global scale is not feasible. The global coastal network will need to be customized locally and regionally based on priorities established by stakeholders in their respective regions. The E.U. Marine Strategy Framework Directive and the U.S. Recommendations of the Interagency Ocean Policy Task Force are important examples of emerging regional scale approaches. The effectiveness of these policies will depend on the co-evolution of ocean policy and the observing system under the auspices of integrated ocean governance.  相似文献   
956.
山东半岛近岸海域生态系统健康综合评价   总被引:3,自引:0,他引:3  
为了构建基于多指标体系的生态系统健康评价方法,作者在调研了大量国内外文献的基础上,通过实证研究和量化分析,对山东半岛近岸海域生态系统健康的现状做出了较为客观的评价。在综合考虑影响海洋生态系统健康的各种因素的基础上,构建了山东半岛近岸海域生态系统健康评价指标体系,从陆源压力、水质状态和生物响应3个方面对山东半岛近岸海域生态系统健康和环境压力进行分析。结果显示:2006年山东半岛近岸海域生态健康状况基本呈现由外海到近岸逐渐变差的态势,其中生态健康状况较差的海域主要集中在莱州湾西南部、烟台北部海域、威海的沿岸海域以及山东半岛东南部海域。  相似文献   
957.
Assessment of vulnerability for natural ecosystem to climate change is a hot topic in climate change and ecology,and will support adapting and mitigating climate change. In this study,LPJ model modified according to features of China's natural ecosystems was employed to simulate ecosystem dynamics under A2,B2 and A1B scenarios. Vulnerability of natural ecosystem to climate change was assessed according to the vulnerability assessment model. Based on eco-geographical regions,vulnerability of natural ecosystem to climate change was analyzed. Results suggest that vulnerability for China's natural ecosystems would strengthen in the east and weaken in the west,but the pattern of ecosystem vulnerability would not be altered by climate change,which rises from southeast to northeast gradually. Increase in ecosystem vulnerable degree would mainly concentrate in temperate humid/sub-humid region and warm temperate humid/sub-humid region. Decrease in ecosystem vulnerable degree may emerge in northwestern arid region and Qinghai-Tibet Plateau region. In the near-term scale,natural ecosystem in China would be slightly affected by climate change. However,in mid-term and long-term scales,there would be severely adverse effect,particularly in the east with better water and thermal condition.  相似文献   
958.
遥感组合指数与不同分类技术结合提取农业用地方法   总被引:1,自引:0,他引:1  
多光谱遥感影像因具有丰富的波谱信息,提高了地表覆盖的辨识能力,利用遥感数据高精度自动提取专题信息是目前研究的热点和难点。本文以北京市ASTER影像为例,通过对城市生态环境中土地类型及其光谱特征规律分析,组合归一化差异植被指数、修正归一化差异水体指数和归一化差异建筑指数三种指数,制作组合指数新影像。对组合指数影像采用基于支持向量机的面向对象分类方法进行农业用地信息提取,同时将该方法分别与基于原始影像、组合指数影像的最大似然及支持向量机的分类方法进行对比分析。实验结果表明:组合归一化差异指数影像压缩了数据维数,降低了覆盖地物相关性,易于农业用地信息提取。对组合指数影像采用基于支持向量机的面向对象分类方法精度达95.701%。  相似文献   
959.
闫太重 《山东地质》2011,(12):60-61,67
章丘市严格规范增减挂钩试点程序,积极走群众自主、自愿、自治的路子,突出“四个创新”,实现“四个突破”,坚持“五项制度”,保障农民群众的知情权、参与权、监督权,真正让农民群众得到实惠,实现了拆迁前农民群众同意、拆迁中农民群众高兴、拆迁整理后农民群众满意的目标。  相似文献   
960.
周鑫  左平  滕厚峰  邹欣庆  陈浩 《海洋通报》2011,30(6):656-661
长三角一体化与江苏沿海开发上升为国家战略,使盐城滨海湿地面临空前的发展压力,如何正确认识滩涂的价值并加以合理利用是制定各项方针政策的前提.运用1987、1992、1997、2002、2007年共5个时相相Landsat数据来获得土地利用和景观的时空变化信息,综合运用直接市场价值法、间接市场价值法、替代成本法、Costa...  相似文献   
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