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排序方式: 共有1891条查询结果,搜索用时 15 毫秒
761.
MARTIN DALLIMER DUGALD TINCH NICK HANLEY KATHERINE N. IRVINE JAMES R. ROUQUETTE PHILIP H. WARREN LORRAINE MALTBY KEVIN J. GASTON PAUL R. ARMSWORTH 《Conservation biology》2014,28(2):404-413
Given that funds for biodiversity conservation are limited, there is a need to understand people's preferences for its different components. To date, such preferences have largely been measured in monetary terms. However, how people value biodiversity may differ from economic theory, and there is little consensus over whether monetary metrics are always appropriate or the degree to which other methods offer alternative and complementary perspectives on value. We used a choice experiment to compare monetary amounts recreational visitors to urban green spaces were willing to pay for biodiversity enhancement (increases in species richness for birds, plants, and aquatic macroinvertebrates) with self‐reported psychological gains in well‐being derived from visiting the same sites. Willingness‐to‐pay (WTP) estimates were significant and positive, and respondents reported high gains in well‐being across 3 axes derived from environmental psychology theories (reflection, attachment, continuity with past). The 2 metrics were broadly congruent. Participants with above‐median self‐reported well‐being scores were willing to pay significantly higher amounts for enhancing species richness than those with below‐median scores, regardless of taxon. The socio‐economic and demographic background of participants played little role in determining either their well‐being or the probability of choosing a paying option within the choice experiment. Site‐level environmental characteristics were only somewhat related to WTP, but showed strong associations with self‐reported well‐being. Both approaches are likely to reflect a combination of the environmental properties of a site and unobserved individual preference heterogeneity for the natural world. Our results suggest that either metric will deliver mutually consistent results in an assessment of environmental preferences, although which approach is preferable depends on why one wishes to measure values for the natural world. Preferencias de Cuantificación para el Mundo Natural Usando Estudios de Valor Monetario y No Monetario. 相似文献
762.
C.N. Almeida J. Roehrig E. Wendland 《Journal of the American Water Resources Association》2014,50(1):101-110
This study presents the implementation of a spatial decision support system (SDSS) named ARENA. The program has been developed based on object‐oriented concepts using the Java programming language. The SDSS is made up of a groundwater simulation tool coupled to an open geographic information system (open GIS). Both the open GIS and groundwater simulation package share common spatial and nonspatial entities during the modeling process. A dedicated interface provides direct access to the GIS data without the need of external files. The finite element method is used to solve the partial differential equation that governs groundwater flow. The system implementation is presented by depicting the main classes and coupling procedures. A study case demonstrates the applicability of the simulation tool. 相似文献
763.
Thomas T. Griffin Raymond A. Ferrara 《Journal of the American Water Resources Association》1984,20(5):777-788
The models available for simulating phosphorus dynamics and trophic state in impoundments vary widely. The simpler empirically derived phosphorus models tend to be appropriate for long-term, steady or near steady state analyses. The more complex ecosystem models, because of computational expense and the importance of input parameter uncertainty, are impractical for very long-term simulation and most applicable for time-variable water quality simulations generally of short to intermediate time frames. An improved model for time variable, long-term simulation of trophic state in reservoirs with fluctuating inflow and outflow rates and volume is needed. Such a model is developed in this paper representing the phosphorus cycle in two-layer (i.e., epilimnion and hypolimnion) reservoirs. The model is designed to simulate seasonally varying reservoir water quality and eutrophication potential by using the phosphorus state variable as the water quality indicator. Long-term simulations with fluctuating volumes and variable influent and effluent flow rates are feasible and practical. The model utility is demonstrated through application to a pumped storage reservoir characteristic of these conditions. 相似文献
764.
David M. Hetrick Andrea L. Sjoreen 《Journal of the American Water Resources Association》2004,40(5):1129-1140
ABSTRACT: Hydrologic Transport Assessment System (HYTRAS) is a software package that models contaminant transport in rivers and streams, including volatilization, adsorption/desorption, sedimentation, settling, and resuspension. Biodegradation, photolysis, and any other process that can be modeled using a first‐order decay constant can be included as well. HYTRAS originally modeled the transport of radionuclides and has recently been expanded to include transport of chemicals. The transport of chemicals has been validated using data from an accidental release of the chemicals disulfoton and thiometon into the Rhine River in 1986. For these chemicals, sorption is not an important process. For the range of measured flow velocities, HYTRAS was found to bound the peak arrival times. For the range of measured degradation rates, HYTRAS was found to bound the peak concentrations within 400 km of the source and bound the peak concentrations within a factor of two out to 700 km. 相似文献
765.
冲突分析在环境领域中的应用 总被引:2,自引:0,他引:2
冲突分析是用来分析冲突局势、预测冲突发展、研究、设计冲突处理方案的一门科学。本文根据国内外研究资料,分析了冲突分析在环境领域中的应用,其中对公共设施选址、污染集中治理投资的分摊、允许排污量在各排污口问的公平分配、水资源集中管理、协调度模型处理环境与经济的冲突、跨行政区河流边界水质标准的确定、资源的开发与保护等进行了重点评述,并指出了冲突分析理论中存在的问题、解决的办法和发展方向。 相似文献
766.
对乡镇企业职工的职业安全卫生知识、态度、行为的调查 总被引:2,自引:0,他引:2
从对某市部分乡镇企业职工的职业安全卫生知识、态度、行为所进行的调查看,不同状况的人群对职业安全卫生知识、态度、习惯有显著性差异。为此,提示职业安全卫生监督管理部门及企业的有关职能部门在职工的职业安全卫生教育中,要加强对文化程度低、年轻、工龄较短的职工的教育,并采用形式多样化手段。另外,职业安全监督管理部门还要加强监督外资企业做好职工的职业安全卫生教育。从职工对职业安全卫生的态度及行为结果看,提出在进行职业安全卫生教育时,要有针对性。不仅要给职工配备劳保用品,更重要的是监督职工经常和正确地使用劳保用品,并养成良好的卫生习惯 相似文献
767.
DynamicsimulationandmodelingofPCPtransportbetweensedimentandwaterLiTie,YeChangming,LeiZhifangResearchCenterforEcoEnviro... 相似文献
768.
ComparisonofsomeatmosphericchemicalmodelingschemesShenJi,ZhaoQianxueResearchCenterforEcoEnviromentalSciences,ChineseAcademy... 相似文献
769.
采用先进的CAD/CAM技术对传统模具设计制造方法进行改造,是提高模具设计制造质量和效率的关键.此文提出基于特征和知识的才法构造精密注塑模设计和制造系统,并介绍了系统的总体方案和系统包含的各模块功能.这一系统是浙江省科委八五攻关项目“精密注塑模设计和制造(CAD/CAM)技术”的核心. 相似文献
770.
CAD技术已逐渐从二维系统向三维实体造型方面转变.以Solidworks作为支撑平台,以Visual Basic和Access为开发工具,应用面向对象的程序开发方法,开发了一个挤压模CAD系统.对该系统的设计做了概括性的描述,并介绍了该系统的软件开发过程中的关键技术. 相似文献