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211.
Asymmetry in traits of sexual relevance may impair copulation behaviour and sexual performance of males, ultimately resulting in a fitness cost. Freshwater crayfish males use chelae, a sexually selected trait, to secure and position the female prior to and during mating. Thus, a relatively large chelae asymmetry, resulting from accidental loss and regeneration of one cheliped after autotomy, could have great consequences for male sexual behaviour. We studied copulatory behaviour and sperm expenditure of males paired to a mated female in Austropotamobius italicus, a freshwater crayfish species where both male and female mate multiply and where last-mating males are able to actively remove previously deposited sperm. We aimed at assessing whether male sperm removal and expenditure varied according to sperm allocated by first-mating males, and according to copulation behaviour and phenotypic traits (carapace length, chelae length and relative chelae asymmetry) of second-mating males. Second-mating males did not adjust their ejaculate size in relation to first-mating male ejaculate, nor to the first-mating male’s sperm removed. Moreover, the amount of sperm removed by second-mating males increased with increasing first-mating males ejaculate size, and first-mating male sperm remaining after removal did not correlate with the original first-mating male ejaculate size. Interestingly, the amount of sperm removed by second-mating males decreased with increasing relative chelae asymmetry, while increasing with male body size. However, second-mating (but not first-mating) asymmetric-clawed males produced larger ejaculates than symmetric-clawed ones. Importantly, the proportion of second-mating male sperm remaining after the two matings did not vary with relative chelae asymmetry nor with body size of second-mating males. Thus, small, asymmetric-clawed crayfish males appear to adopt sperm allocation tactics that allow them to fully compensate for their inferior sperm removal ability.  相似文献   
212.
Current Trends in Plant and Animal Population Monitoring   总被引:3,自引:0,他引:3  
Abstract:  Animal and plant population monitoring programs are critical for identifying species at risk, evaluating the effects of management or harvest, and tracking invasive and pest species. Nevertheless, monitoring activities are highly decentralized, which makes it difficult for researchers or conservation planners to get a good general picture of what real-world monitoring programs actually entail. We used a Web-based survey to collect information on population monitoring programs. The survey focused on basic questions about each program, including motivations for monitoring, types of data being collected, spatiotemporal design of the program, and reasons for choosing that design. We received responses from 311 people involved in monitoring of various species and used these responses to summarize ongoing monitoring efforts. We also used responses to determine whether monitoring strategies have changed over time and whether they differed among monitoring agencies. Most commonly, monitoring entailed collection of count data at multiple sites with the primary goal of detecting trends. But we also found that goals and strategies for monitoring appeared to be diversifying, that area-occupied and presence–absence approaches appeared to be gaining in popularity, and that several other promising approaches (monitoring to reduce parameter uncertainty, risk-based monitoring, and directly linking monitoring data to management decisions) have yet to become widely established. We suggest that improved communication between researchers studying monitoring designs and those who are charged with putting these designs into practice could further improve monitoring programs and better match sampling designs to the objectives of monitoring programs.  相似文献   
213.
水资源配置大致存在完全政府配置、完全市场配置和准市场配置3种模式。中国正处于水权制度改革的过程中,水资源配置制度有从完全政府配置转向依靠市场配置的趋势。新制度经济学的交易成本理论和租值消散理论可以为新的水权制度的设计和选择提供依据。水资源的不同配置制度对应着相应的交易成本,相对较好的制度应该能在扣除交易成本之后获得较多的社会净租值。目前我国水资源管理的当务之急是根据经济理性,科学地界定好水资源的公有和私有权利,并由完全政府管制向市场体制转型。  相似文献   
214.
ABSTRACT

Disaster management spans actions before, during, and after disaster events. Changes in the roles and functions of local governments before a disaster can influence other stages of disaster management. After a chemical spill in 2012, South Korean hazardous chemical management tasks were returned to the central government and local governments’ roles and functions were reduced. To identify associated issues and enhance the hazardous chemical management system, this study analyzed changes in laws and policies and conducted interviews with stakeholders. While the changes helped with centralization, reinforcement, and specification, some loopholes were discovered. The information and human resource capacities of local governments and intra – and intergovernmental relations issues have hindered their active participation before and during chemical disasters. These loopholes can be addressed through institutional enhancements for local governments, such as including them in monitoring hazardous chemical handling facilities, developing codes articulating the division of tasks among departments within them, and providing adequate incentives for them to increase their personnel. This study provides empirical data that informs ongoing debates about the centralization and devolution of disaster management by linking local governments’ ordinary management systems to their disaster management activities.  相似文献   
215.
新安江流域生态补偿财政支出效率研究   总被引:1,自引:1,他引:0       下载免费PDF全文
在水环境保护长期受到高度重视的背景下,开展流域生态补偿试点是我国保护流域水环境的重要手段。目前我国多为政府主导型流域生态补偿,补偿资金全部来源于财政资金,提高财政支出效率可以让有限的财政资金发挥其最大效用。为明确流域生态补偿试点中的财政支出效率,本文以我国首个跨省界流域生态补偿试点——新安江流域生态补偿试点为案例对象,构建流域生态补偿财政支出效率评价模型,并建立评价指标体系。通过选取试点在2012—2017年的生态补偿财政支出进行效率测算与效率评价,结果显示,财政支出纯技术效率6年均值处在0.9以上的高水平,总体表现较好,但仍有改进空间;规模效率值较低是造成财政支出效率表现不佳的主要原因,生态补偿财政资金的配置规模急需完善。建议提高财政资金的管理水平,有针对性地实施生态补偿项目,建立流域和区域相结合的流域治理体系。  相似文献   
216.
"十一五"、"十二五"规划时期,中国单位GDP能耗、SO_2排放总量、COD排放总量等节能减排指标均实现了国家规划目标,这与"十五"计划三项指标均未完成形成鲜明对比。现有研究对此的解释存在宏观和微观层面上的不一致。其重要原因在于现有研究将环境绩效改善的原因完全归于行政奖惩所体现的正式制度的作用,而忽视了非正式制度对节能减排绩效的积极影响。本文建构了以包含正式激励和非正式激励的二元委托代理激励模型为基础的分析框架,利用基于717名不同级别官员的问卷数据,采用结构方程方法对上述模型进行了检验。实证结果表明,与约束性指标相关的正式制度中规定的11项奖惩措施所产生的激励对官员的环境治理行为力度并没有显著影响,而体现为顺应中央政府导向和上级领导注意力所代表的非正式制度激励对官员环境治理行为力度产生了显著影响。非正式制度激励对环境治理行为力度的影响存在两条路径。在第一条路径中,官员压力是中介变量,即非正式制度产生对官员压力的影响,官员压力又进一步影响官员环境治理行为。在这一路径中,晋升偏好、服从偏好为正向调节变量,正式奖惩的执行严格程度为负向调节变量。这一路径表明,官员晋升偏好越强、正式奖惩执行严格程度越弱,非正式制度激励对地方官员压力的影响越大;官员服从上级偏好程度越强,官员压力对环境治理行为力度的影响越大。在第二条路径中,非正式制度激励被认为直接影响环境治理行为力度,服务偏好是正向调节变量。这一路径表明,地方官员为人民服务的偏好越强,非正式激励对环境治理行为的影响越大。本文的研究发现调和了环境政策执行领域的理论冲突,为深化对中国"压力型"体制的理解提供实证证据。  相似文献   
217.
当政府基于公共利益对企业实施规制,政府所代表的公共利益与龙头企业的经济利益冲突时,政府的规制行为与规制效率是否会受龙头企业影响?已有的研究较少涉及这一公共管理的重要问题。本研究从环境规制视角出发,基于1999—2013年的中国31个省级层面的面板数据,结合工业企业数据库微观数据,在省级层面实证检验了当存在利益冲突和规制能力约束时,区域环境规制水平是否会受到龙头企业以规模衡量的能力影响;如是,其方向和机制又是什么。本文研究发现:(1)龙头企业规模越大,区域环境规制水平越严格;(2)龙头企业规模对区域环境规制的影响主要通过两种路径实现,一是龙头企业所在行业的区域经济地位,行业的区域经济地位越重要,越容易引来政府的环境规制关注;二是龙头企业在所在行业的经济地位,某企业在行业的比重越高,越容易引来政府的环境规制关注;(3)龙头企业规模与区域环境规制水平间关系是政府有限环境规制能力有效运用的结果,当政府规制能力不足时,政府在规制中会"抓大放小",重点加强对龙头企业的环境规制;随着政府规制能力上升,企业规模与区域环境规制水平的正相关关系不仅回归系数会逐步下降,而且会在统计上不再显著;最终,当政府掌握充分的环境规制能力后,企业的规模可能会在降低区域环境规制水平上发挥一定作用。本文的研究结果证实当政府与企业存在利益博弈时,政府的利益首先得到满足,仅当政府的利益得到满足后,企业才可能利用其实力影响政府规制以获取规制利益最大化。本文的研究一方面消除了"政商勾结"污染环境的忧虑,另一方面也提示要严格限制政府这只"看得见的手"的利益诉求范围。  相似文献   
218.
山东省探索开展了空气质量监测"转让-经营"模式改革,在体制上科学划分监测事权,实行"谁考核、谁监测",省级环保部门负责17个设区城市环境质量的监督监测,污染源监督监测下放到市、县级环保部门;在机制上实行政府购买服务,对全省空气质量自动监测站实行"监测设备有偿转让,专业队伍运营维护,专业机构移动比对,环保部门质控考核,政府购买合格数据"的"转让-经营"模式。通过改革,监测数据质量和监测公信力得到进一步提高,有效避免了可能的行政干预,降低了监测成本,引导了环保服务业的发展,可以为其他省、市贯彻落实生态环境监测体制改革和地方监测事权上收工作提供一些参考。  相似文献   
219.
环境监测市场化若干问题的思考   总被引:11,自引:8,他引:3  
在环境监测市场化内涵辨析的基础上,界定了环境监测市场化包括非公共服务属性的环境监测使市场起决定性作用和公共服务属性的环境监测引入市场机制两层涵义,分析了环境监测市场化中政府与市场的职责和定位,提出了建立健全环境监测市场机制需要重点研究的若干问题。  相似文献   
220.
City action is critical to achieving global visions for sustainability such as the UN’s Sustainable Development Goals (SDGs). However, SDG ‘localisation’ is complex procedure, with divergent outcomes depending on context and diverse city processes. This paper considers the operational challenges faced by city actors in taking on the SDGs, and subsequent implications for initiating local (and global) sustainability transitions. We analyse emergent approaches to SDG localisation within the Asia–Pacific, using a policy analysis framework (transition management) to assess transformation potential. We find that SDG localisation can influence urban sustainability, but effective implementation requires sufficient data, resourcing, and guidance—which are not readily, nor equally available to all city governments. City-to-city peer learning can accelerate SDG uptake, but realising the transformative ambition set out by the SDGs will require an approach to localisation that clearly demonstrates why and how any city government can and should engage with global sustainability frameworks.  相似文献   
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