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911.
两栖动物种群衰退研究进展 总被引:16,自引:0,他引:16
过去50a中,全球范围内许多两栖动物种群显著衰退,一些种类已经灭绝.研究发现,这类现象的出现与人类活动日益加强密切相关,生态环境的破坏,污染的排放、气候的改变、野生动植物疾病的流行等因素是导致这一现象的主要原因.本文总结介绍了近年来国际上本领域的最新研究成果与动态,并对我国的研究现状和未来作了讨论.图1参40 相似文献
912.
Estimating the Effect of Protected Lands on the Development and Conservation of Their Surroundings 总被引:1,自引:0,他引:1
ROBERT I. McDONALD †† CHRIS YUAN-FARRELL† CHARLES FIEVET‡ MATTHIAS MOELLER§ PETER KAREIVA† DAVID FOSTER TED GRAGSON‡ ANN KINZIG§ LAUREN KUBY CHARLES REDMAN 《Conservation biology》2007,21(6):1526-1536
Abstract: The fate of private lands is widely seen as key to the fate of biodiversity in much of the world. Organizations that work to protect biodiversity on private lands often hope that conservation actions on one piece of land will leverage the actions of surrounding landowners. Few researchers have, however, examined whether protected lands do in fact encourage land conservation nearby or how protected lands affect development in the surrounding landscape. Using spatiotemporal data sets on land cover and land protection for three sites (western North Carolina, central Massachusetts, and central Arizona), we examined whether the existence of a protected area correlates with an increased rate of nearby land conservation or a decreased rate of nearby land development. At all sites, newly protected conservation areas tended to cluster close to preexisting protected areas. This may imply that the geography of contemporary conservation actions is influenced by past decisions on land protection, often made for reasons far removed from concerns about biodiversity. On the other hand, we found no evidence that proximity to protected areas correlates with a reduced rate of nearby land development. Indeed, on two of our three sites the development rate was significantly greater in regions with more protected land. This suggests that each conservation action should be justified and valued largely for what is protected on the targeted land, without much hope of broader conservation leverage effects. 相似文献
913.
Anthony E. J. 《Journal of Coastal Conservation》1997,3(1):169-178
Beach conservation and management on the high-value French Riviera in southeastern France have had mixed fortunes in shoreline
economic development strategies over the past half century. Prior to 1965, socio-economic growth related to immigration and
tourism resulted in considerable pressure on the coastal zone, leading in particular to beach erosion and degradation of beach
environmental quality. Between 1965 and 1980, over 20% of the 132 km-long French Riviera was permanently altered through the
implantation of yachting harbours and reclamation fill structures, while beach-based recreation had a rather low ranking as
a development choice, except in the two major resorts of Cannes and Nice which exhibit a densely urbanized seafront. On this
preponderantly boldrocky coast, the mediocre recreational value inherited by many of the beaches from the regional geologic
setting, and from development pressures and earlier errors in coastal management, left them vulnerable to appropriation and
so-called ‘valorization’ by yachting harbour and estate developers.
Over the last decade, artificial shoreline development has virtually ceased, in response to several more or less interrelated
factors. These include relative stagnation of socio-economic growth, increasing development and maintenance costs of yachting
harbours, saturation of the yachting harbour market as a result of the burgeoning of new, often cheaper, resorts and of reconversion
of commercial and shipbuilding ports to leisure ports in the Mediterranean, more stringent legislation, since 1986, on the
implantation of residential and major engineering structures on the coastline, pressure for conservation of the cultural and
environmental heritage, and greater demand for beach recreational space. This situation has forced a diversification of shore-based
activities, as it has been realised that better managed beaches may balance economic aspirations while contributing to enhanced
environmental quality and sensible shoreline conservation. This change in strategy has entailed considerable efforts and money
on the improvement of coastal water quality, the provision of amenities for beach-goers, and especially the nourishment of
eroding beaches and the creation of several artificial beaches. The extent to which beaches will continue to play a role in
the sustainable development of French Riviera resorts will depend largely on the capacity of local authorities to maintain
environmental quality in the face of inherited and persistent handicaps such as beach erosion. 相似文献
914.
Stephen W. Sawyer 《Journal of the American Water Resources Association》1984,20(5):679-685
States have the potential to play a major role in moving water conservation from conferences and reports that identify its advantages to actual practice. The research identifies four generic “strategies” that categorize the states' approaches toward conservation and reports on the states' current conservation activities. The four strategies are: reliance on agricultural advisors, leverage incentives, performance standards, and mandatory actions. Four levels of state conservation activity exist. California and Florida maintain the most extensive programs; Arizona, Massachusetts, New Jersey, North Carolina, and Oklahoma also have numerous programs but significantly lower staff commitments; eight additional states maintain more modest conservation effotts. Elsewhere, state directed conservation actions remain minimal and limited to those provided as agricultural advice. The study found support for water conservation the norm among water supply planners. 相似文献
915.
采用室内模拟试验的方法,研究了水位、氮沉降、电导率等单因素对土壤呼吸的影响,以及三因素对土壤碳储量交互影响的响应面优化,并得到了土壤碳储量最大的最优方案。结果表明:对于单因素试验而言,过高或过低的水位及氮沉降梯度均会对土壤呼吸造成不利影响,而电导率的增加对土壤呼吸呈显著抑制作用,当水位、氮沉降、电导率分别为-9 cm、20 g/m2、0.3 d S/m时,土壤90 d累积呼吸总量最大,分别为84.95μmol/(m2·s)、92.88μmol/(m2·s)和85.70μmol/(m2·s);响应面优化分析中,北大港芦苇湿地碳储量的最优方案为水位-5.49 cm,电导率3.52 ds/m,氮沉降13.40 g/m2,在此条件下预测的理论碳储量最大值为8.62 g/kg。该优化方案可为天津滨海湿地资源的合理开发利用及湿地保育政策的制定等提供参考。 相似文献
916.
《组织行为杂志》2017,38(8):1183-1195
Using conservation of resources theory, we challenge traditional unity of command models of leadership and propose that a dual‐leadership framework can serve as a potential solution to the inherent challenges of innovation. Leading for innovation demands are depicted as uniquely disparate from other forms of leadership, resulting in several types of conflict and resource depletion for individual leaders. We contend that this exploration–exploitation role conflict and the resulting need to manage incongruent role identities produce stress, strain, and resource depletion that in turn hamper innovative goal achievement for both a single leader directly and via subordinates more indirectly. We propose, however, that as an extension of the resource investment tenet of the conservation of resources theory, a dual‐leadership approach may alleviate many of these challenges for innovation. Specifically, the addition of a second leader can add resources to innovation and in turn decrease the role conflict inherent in managing the generation and implementation of creative ideas. Limitations and areas for future research are offered. 相似文献
917.
为分析长江经济带产业排水量变化的驱动因素,以2002年、2007年和2012年长江经济带11省市投入产出表、排水估计量为基础,利用基于投入产出的结构分解法对各省市数据进行比较静态分析,对驱动产业排水量变化的因素进行分解及定量评估,包括节水减排效应、投入结构效应、需求结构效应及规模效应.结果表明:①长江经济带产业排水量由增长趋势变为下降趋势,2002—2007年排水量增长了16.9%,2007—2012年排水量降低了0.4%,2002年、2007年、2012年产业平均耗水率为46%,上海市、江苏省等省市产业排水量下降趋势明显.②规模效应是驱动各省市产业排水增加的主要因素,其在2002—2007年、2007—2012年带动排水量分别增长了67%和61%;规模效应影响逐渐分化,上海市、江苏省、浙江省规模效应带动产业排水量增幅逐渐减弱.③节水减排效应是驱动排水量减少的最主要因素,其在2002—2007年、2007—2012年带动排水量分别减少了35%和60%,节水减排效应影响逐渐增强,各省市排水强度明显降低.④长江经济带大部分省市的需求结构效应驱动产业排水量不断减少,其驱动力的绝对值呈增长趋势;投入结构效应对产业排水量的驱动力较弱且变化规律性不明显.建议长江经济带通过技术进步、应用创新等提高清洁生产能力,通过需求及投入结构优化带动产业结构调整,对进一步降低产业排水量具有一定价值. 相似文献
918.
实现长江大保护环境与经济可持续发展对打好长江保护修复攻坚战、持续推动长江经济带实现高水平保护和高质量发展具有重要意义.为了系统研究长江大保护的环境与经济可持续性,探索以生态优先、绿色发展为导向的高质量发展新路子,在查阅分析文献资料和对政府相关部门和企业开展实地调研访谈的基础上,梳理长江经济带11省市大保护工作的基本情况,分析环境与经济可持续发展面临的问题与挑战,并提出有针对性的对策建议.结果表明:①当前长江大保护各项工作稳步高效推进,取得了阶段性进展和成效.②长江大保护面临生态环境保护系统性不足、资金缺口大且渠道窄、运营效率低、政策支持力度不足等问题.③建议长江经济带在规划、管理、模式等方面系统推进,拓宽长江大保护资金渠道,增强规模化运营效益,加大对长江大保护的政策支持和倾斜.研究显示,长江大保护虽已取得初步成效,但环境与经济可持续发展形势依然严峻,需要在生态环境系统保护、投融资、项目建设运营、政策支持等方面进一步加强. 相似文献
919.
复合铜盐对有机废弃物高温好氧堆肥的保氮效果 总被引:3,自引:0,他引:3
高温好氧堆肥是资源化利用有机废弃物的途径之一,但堆肥过程中氮素损失严重.本文以复合铜盐CCS为保氮剂,粪便混合物为堆肥原料,通过单因素和正交实验,研究了C/N比(20、30、35)、含水率w(50%、55%、60%)、CCS添加量m(1.2%、1.4%、1.6%)等因素对高温好氧堆肥中氮素的影响,初步探讨了氮素固定的机理.实验结果表明,最佳氮素固定条件为:C/N=20、w=60%、m=1.4%,在此条件下,总氮损失减少率(L)高达62.78%.与其他保氮剂对比发现,复合铜盐具有添加量少、总氮损失减少率较高、成本适中等优点,表明复合铜盐适宜用作堆肥过程中的保氮剂.氮素固定的机理可能是铜离子与铵根离子络合. 相似文献
920.