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981.
东北商品粮基地粮食生产的区域分异   总被引:32,自引:3,他引:29  
论文以商品粮基地县为研究单元,运用数理统计和GIS空间分析结合的方法,揭示东北商品粮基地县粮食总产的区域差异。研究结果表明:①粮食总产低于平均水平的商品粮基地县占多数,高于平均水平的基地数量仅占36.36%,但粮食产量占全部基地县粮食总产量的64.74%;②粮食生产基本上形成了以玉米、大豆、水稻为主的生产能力格局,粮食总产的区域差异小于分品种粮食作物内部的区域差异;③从省域尺度看,粮食总产高于平均水平的基地县84.6%分布在黑龙江和吉林两省,粮食生产布局的区域化、专业化趋势明显,大宗粮食作物进一步向产粮大县集中;④从区域尺度看,粮食总产的空间格局高低交错,集中在以松嫩平原中部黑土区、辽河平原和三江平原为重心的平原地区,有由中部平原地区向周边递减的趋势。回归分析表明,播种面积的区域差异是导致商品粮基地县粮食总产区域分异的主要原因,农业现代化水平对其具有重要影响。应加强商品粮基地建设,加大中低产田的改造力度,走以提高粮食单产来提高粮食综合生产能力的内涵式发展道路。  相似文献   
982.
基于多时相土地利用图与遥感影像资料,建立空间研究网格,通过土地利用扩展强度指数的空间分析,对1947~2002年上海市建成区居住用地扩展模式、强度及空间分异特征进行了研究。结果表明:①上海市建成区居住用地空间扩展并不是持续增长的,其扩展强度与速度均从建国初期开始减小,在1964~1979年期间达到最低值后又逐渐增大,总体上表现为先降后升的发展变化;②居住用地扩展模式随时间发生较大变化,由建国初期以核心建成区为主的渐进式扩展(1947~1964年)转变为跳跃式扩展(1964~1988年),到近些年又发展成兼具渐进扩展与跳跃扩展特征的混合扩展模式(1988~2002年),城市用地功能由简单趋于复杂和多元化;③不同时期居住用地扩展过程差异较大,其行为特征受国家宏观政策及社会经济发展等因素的影响,可以为复杂的城市扩展动力机制研究提供更多素材。  相似文献   
983.
三江源地区土壤保持功能空间分析及其价值评估   总被引:13,自引:1,他引:12       下载免费PDF全文
在地理信息系统的支持下,利用已有的资料,将三江源地区划分为1km×1km的栅格,并以栅格为单元对其生态系统土壤保持功能进行分析和计算.运用通用土壤流失方程研究了该地区生态系统土壤侵蚀量和土壤保持量及其空间分布,并利用市场价值法、机会成本法和影子工程法评估了土壤保持功能的价值.研究表明,三江源地区生态系统土壤保持总量为1.04×109t/a,其价值总计为1.25×109元/a.其中保持土壤养分的经济价值为1.10×109元/a,减少废弃土地的经济价值为1.64×107元/a,减少泥沙淤积的经济价值为1.34×108元/a.  相似文献   
984.
提出了一套针对CO2驱油开采区生态监测的空间信息图谱方法。在分析生态监测任务的基础上,给出了图谱数据组织模型和生态监测方法。山东某油田生态监测实例项目应用结果表明,此方法能够有效组织数据并从中发掘生态信息,长期连续监测可以实现CO2逸散风险诊断和生态影响评估的目的。  相似文献   
985.
Marine fish stocks are in many cases extracted above sustainable levels, but they may be protected through restricted‐use zoning systems. The effectiveness of these systems typically depends on support from coastal fishing communities. High management costs including those of enforcement may, however, deter fishers from supporting marine management. We incorporated enforcement costs into a spatial optimization model that identified how conservation targets can be met while maximizing fishers’ revenue. Our model identified the optimal allocation of the study area among different zones: no‐take, territorial user rights for fisheries (TURFs), or open access. The analysis demonstrated that enforcing no‐take and TURF zones incurs a cost, but results in higher species abundance by preventing poaching and overfishing. We analyzed how different enforcement scenarios affected fishers’ revenue. Fisher revenue was approximately 50% higher when territorial user rights were enforced than when they were not. The model preferentially allocated area to the enforced‐TURF zone over other zones, demonstrating that the financial benefits of enforcement (derived from higher species abundance) exceeded the costs. These findings were robust to increases in enforcement costs but sensitive to changes in species’ market price. We also found that revenue under the existing zoning regime in the study area was 13–30% lower than under an optimal solution. Our results highlight the importance of accounting for both the benefits and costs of enforcement in marine conservation, particularly when incurred by fishers. Justificación de los Costos de Aplicación en la Asignación Espacial de Zonas Marinas  相似文献   
986.
Conservation focuses on maintaining biodiversity and ecosystem functioning, but gaps in our knowledge of species biology and ecological processes often impede progress. For this reason, focal species and habitats are used as surrogates for multispecies conservation, but species‐based approaches are not widely adopted in marine ecosystems. Reserves in the Solomon Islands were designed on the basis of local ecological knowledge to conserve bumphead parrotfish (Bolbometopon muricatum) and to protect food security and ecosystem functioning. Bumphead parrotfish are an iconic threatened species and may be a useful surrogate for multispecies conservation. They move across tropical seascapes throughout their life history, in a pattern of habitat use that is shared with many other species. We examined their value as a conservation surrogate and assessed the importance of seascape connectivity (i.e., the physical connectedness of patches in the seascape) among reefs, mangroves, and seagrass to marine reserve performance. Reserves were designed for bumphead parrotfish, but also enhanced the abundance of other species. Integration of local ecological knowledge and seascape connectivity enhanced the abundance of 17 other harvested fish species in local reserves. This result has important implications for ecosystem functioning and local villagers because many of these species perform important ecological processes and provide the foundation for extensive subsistence fisheries. Our findings suggest greater success in maintaining and restoring marine ecosystems may be achieved when they are managed to conserve surrogate species and preserve functional seascape connections. Incorporación de Especies Sustitutas y de Conectividad Marina para Mejorar los Resultados de Conservación  相似文献   
987.
Policy documents advocate that managers should keep their options open while planning to protect coastal ecosystems from climate‐change impacts. However, the actual costs and benefits of maintaining flexibility remain largely unexplored, and alternative approaches for decision making under uncertainty may lead to better joint outcomes for conservation and other societal goals. For example, keeping options open for coastal ecosystems incurs opportunity costs for developers. We devised a decision framework that integrates these costs and benefits with probabilistic forecasts for the extent of sea‐level rise to find a balance between coastal ecosystem protection and moderate coastal development. Here, we suggest that instead of keeping their options open managers should incorporate uncertain sea‐level rise predictions into a decision‐making framework that evaluates the benefits and costs of conservation and development. In our example, based on plausible scenarios for sea‐level rise and assuming a risk‐neutral decision maker, we found that substantial development could be accommodated with negligible loss of environmental assets. Characterization of the Pareto efficiency of conservation and development outcomes provides valuable insight into the intensity of trade‐offs between development and conservation. However, additional work is required to improve understanding of the consequences of alternative spatial plans and the value judgments and risk preferences of decision makers and stakeholders. Minimizando el Costo de Mantener Opciones Abiertas para la Conservación en un Clima Cambiante  相似文献   
988.
The efficacy of protected areas varies, partly because socioeconomic factors are not sufficiently considered in planning and management. Although integrating socioeconomic factors into systematic conservation planning is increasingly advocated, research is needed to progress from recognition of these factors to incorporating them effectively in spatial prioritization of protected areas. We evaluated 2 key aspects of incorporating socioeconomic factors into spatial prioritization: treatment of socioeconomic factors as costs or objectives and treatment of stakeholders as a single group or multiple groups. Using as a case study the design of a system of no‐take marine protected areas (MPAs) in Kubulau, Fiji, we assessed how these aspects affected the configuration of no‐take MPAs in terms of trade‐offs between biodiversity objectives, fisheries objectives, and equity in catch losses among fisher stakeholder groups. The achievement of fisheries objectives and equity tended to trade‐off concavely with increasing biodiversity objectives, indicating that it is possible to achieve low to mid‐range biodiversity objectives with relatively small losses to fisheries and equity. Importantly, the extent of trade‐offs depended on the method used to incorporate socioeconomic data and was least severe when objectives were set for each fisher stakeholder group explicitly. We found that using different methods to incorporate socioeconomic factors that require similar data and expertise can result in plans with very different impacts on local stakeholders.  相似文献   
989.
Protected area delineation and conservation action are urgently needed on marine islands, but the potential biodiversity benefits of these activities can be difficult to assess due to lack of species diversity information for lesser known taxa. We used linear mixed effects modeling and simple spatial analyses to investigate whether conservation activities based on the diversity of well‐known insular taxa (birds and mammals) are likely to also capture the diversity of lesser known taxa (reptiles, amphibians, vascular land plants, ants, land snails, butterflies, and tenebrionid beetles). We assembled total, threatened, and endemic diversity data for both well‐known and lesser known taxa and combined these with physical island biogeography characteristics for 1190 islands from 109 archipelagos. Among physical island biogeography factors, island area was the best indicator of diversity of both well‐known and little‐known taxa. Among taxonomic factors, total mammal species richness was the best indicator of total diversity of lesser known taxa, and the combination of threatened mammal and threatened bird diversity was the best indicator of lesser known endemic richness. The results of other intertaxon diversity comparisons were highly variable, however. Based on our results, we suggest that protecting islands above a certain minimum threshold area may be the most efficient use of conservation resources. For example, using our island database, if the threshold were set at 10 km2 and the smallest 10% of islands greater than this threshold were protected, 119 islands would be protected. The islands would range in size from 10 to 29 km2 and would include 268 lesser known species endemic to a single island, along with 11 bird and mammal species endemic to a single island. Our results suggest that for islands of equivalent size, prioritization based on total or threatened bird and mammal diversity may also capture opportunities to protect lesser known species endemic to islands. Beneficios de los Taxa Poco Estudiados para la Conservación de la Diversidad de Aves y Mamíferos en Islas  相似文献   
990.
Conservation of representative facets of geophysical diversity may help conserve biological diversity as the climate changes. We conducted a global classification of terrestrial geophysical diversity and analyzed how land protection varies across geophysical diversity types. Geophysical diversity was classified in terms of soil type, elevation, and biogeographic realm and then compared to the global distribution of protected areas in 2012. We found that 300 (45%) of 672 broad geophysical diversity types currently meet the Convention on Biological Diversity's Aichi Target 11 of 17% terrestrial areal protection, which suggested that efforts to implement geophysical diversity conservation have a substantive basis on which to build. However, current protected areas were heavily biased toward high elevation and low fertility soils. We assessed 3 scenarios of protected area expansion and found that protection focused on threatened species, if fully implemented, would also protect an additional 29% of geophysical diversity types, ecoregional‐focused protection would protect an additional 24%, and a combined scenario would protect an additional 42%. Future efforts need to specifically target low‐elevation sites with productive soils for protection and manage for connectivity among geophysical diversity types. These efforts may be hampered by the sheer number of geophysical diversity facets that the world contains, which makes clear target setting and prioritization an important next step.  相似文献   
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