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291.
区域环境质量与经济发展关系模型研究 总被引:18,自引:2,他引:16
环境库兹涅茨曲线是目前环境经济领域被广泛引用的一个计量模型。针对当前人们大多通过实际观测资料,利用回归分析,估计环境质量转折点,而理论研究相对较少的现状,从社会福利最大化角度出发,通过设定物品消费偏好指数,建立了一个两物品模型。通过数学推理,首先推导出了区域环境最佳投资水平,在此基础上从理论上证明了环境库兹涅茨曲线存在的依据,以及在环境质量最低点和环境质量发生根本性好转的转折点的社会总投资水平。研究表明,环境质量演化过程曲线取决于社会经济发展状况,它与非环境物品生产函数和排污生产函数的技术参数,居民收入水平以及对环境物品和非环境物品的消费偏好,国民收入分配政策等有关,而非仅仅与经济增长状况有关。因此,在经济发展过程中适时地调整产业结构和国民收入分配政策、采用新技术、提倡合理的消费观念等是加速环境质量演化过程的重要措施。 相似文献
292.
随着科学发展观的日益深入人心,发展循环经济越来越得到广泛的认同。新疆作为一个自然生态条件比较脆弱的省区,发展循环经济,进一步优化资源的配置,充分挖掘资源潜力,显得尤为重要。为此,笔者根据多年从事自治区经济社会发展研究的实践经验。结合新疆当前发展循环经济的优势领域,提出了新疆应予优先发展的几个项目。 相似文献
293.
Dennis Wichelns 《Journal of the American Water Resources Association》1991,27(4):585-592
ABSTRACT: Increasing block-rate prices for irrigation water were implemented during 1989 in a 10,000-acre irrigation district in California's San Joaquin Valley. The program motivated improvements in irrigation practices that reduced the volume of water delivered to farm fields and the volume of drain water collected in on-farm drainage systems. The ratio of net crop water requirements to field deliveries increased from 0.65 in 1988 to 0.73 in 1989. The volume of drain water collected at a subset of 20 drainage systems was reduced by 351.1 acre-feet (11.5 percent). Estimated loads of salt, boron, and selenium were reduced by 2,407 tons (11.0 percent), 3.33 tons (11.0 percent), and 0.07 tons (9.2 percent). 相似文献
294.
Barbara A. Rosensteel Peter F Strom 《Journal of the American Water Resources Association》1991,27(6):957-965
ABSTRACT: Sediments from the Pompton and Passaic Rivers at Two Bridges were analyzed for potentially available phosphorus fractions and total phosphorus (TP). Water samples from the same sites were analyzed for dissolved phosphorus, TP, suspended solids (SS), and volatile SS. Significant negative correlations between river TP concentrations and flow were observed. However, storm flows resulted in increases in TP and SS concentrations and flux (loadings). Most of the increase in river P loading at high flow was in the dissolved fraction, suggesting that the sediments may be a large source of dissolved P. Concentrations of potentially available P in the sediments ranged from 140 to 1310 times the TP concentration in the overlying water. According to a modified Vollenweider model, current P concentrations in the Pompton and Passaic Rivers will result in excessive P loading in the Wanaque Reservoir if even small volumes of river water are pumped to the reservoir through the recently completed Wanaque South pipeline. Reductions in sewage treatment plant effluent P concentrations alone will not produce sufficient decreases in river phosphorus concentrations to avoid this predicted overloading and eutrophication. 相似文献
295.
Ronald L. Miller 《Journal of the American Water Resources Association》1978,14(6):1503-1506
ABSTRACT: Arizona's water pollution control program is based on authorties of Arizona Revised Statutes and Public Law 92–500, the Federal Water Pollution Control Act Amendments of 1972. The primary areas of this program are monitoring, facility inspections, plan review, planning, discharge permits and grants for the construction of publicly-owned waste water treatment facilities. The discharge permit program deals with control of point-source discharges and is administered by the United States Environmental Protection Agency. The planning and construction grants programs are administered by the State Water Quality Control Council and are implemented by the Bureau of Water Quality Control, which serves as staff to the Council. There are several challenges that face the State in this program. First is the adaptation of the “eastern law” to deal with Arizona's water quality problems. Second is to address problems caused by a long history of “laissez-faire” environmental quality management. Third is a mutual cooperation and coordination among the many entities involved in water resources management. Areas of particular interest in the State's program is the process setting water quality standards and the involvement of people of diversified backgrounds in the field of areawide planning under Section 208 of the Federal Water Pollution Control Act, which is primarily concerned with non-point sources of water pollution. 相似文献
296.
Robert C. Ostry 《Journal of the American Water Resources Association》1982,18(1):99-104
ABSTRACT: The Grand and Saugeen Rivers in southern Ontario were chosen for study as pilot watersheds under the Pollution From Land Use Activities Reference Group (PLUARG) study. The pilot watersheds have adjacent headwater areas and are physically similar in geology, physiography, and climate. Significant differences in water quality between the watersheds at their outlets are attributed to land use and population differences. The major pollutant sources in the two pilot watersheds were identified as trace elements from urban runoff and point source discharges; phosphorus from agricultural and urban runoff and private waste disposal; chloride from transportation corridors; and sediment and nitrogen from agricultural runoff. Yields at the watershed outlets were similar for suspended sediment and two to three times as high in the Grand River for phosphours, nitrogen, chloride, and lead. The higher phosphorus and nitrogen levels were attributed to larger point source inputs and the higher proportion of agricultural activity, comprising 75 percent of the Grand River basin compared to 64 percent in the Saugeen River basin. Similarly, the higher chloride and lead levels were attributed to an order of magnitude larger population and three times as much urban land in the Grand River basin compared to the Saugeen River basin. 相似文献
297.
298.
矿井提升机的安全可靠性分析与设计 总被引:11,自引:2,他引:11
矿井提升机是井下作业提升物料和人员的关键设备 ,素有矿井咽喉之称。安全、可靠与高效是提升机设计与分析的基本准则与要求。笔者概要分析了矿井提升机的安全可靠性 ;提出了相应的设计要点 ,并对各子系统中相对薄弱环节的安全可靠性进行了探讨。以上科研成果 ,为提升机械的进一步研究与开发提供了一定的理论参考依据 相似文献
299.
本文根据圆形烟道采样点划分原则,给出了一种方便适用的采样点距烟道内壁的距离公式,并就现有文献中采样点距烟壁的距离值表格的误差进行了修正。 相似文献
300.
Ecological risk assessment provides a methodology for evaluating the threats to ecosystem function associated with environmental
perturbations or stressors. This report documents the development of a conceptual model for assessing the ecological risk
to the water quality function (WQF) of bottomland hardwood riparian ecosystems (BHRE) in the Tifton-Vidalia upland (TVU) ecoregion
of Georgia. Previus research has demonstrated that mature BHRE are essential to maintaining water quality in this portion
of the coastal plain. The WQF of these ecosystems is considered an assessment endpoit—an ecosystem function or set of functions
that society chooses to value as evidenced by laws, regulations, or common usage. Stressors operate on ecosystems at risk
through an exposure scenario to produce ecological effects that are linked to loss of the desired function or assessment end
point. The WQF of BHRE is at risk because of the ecological and environmental quality effects of a suite of chemical, physical,
and biological stressors. The stressors are related to nonpoint source pollution from adjacent land uses, especially agriculture;
the conversion of BHRE to other land uses; and the encroachment of domestic animals into BHRE. Potential chemical, physical,
and biological stressors to BHRE are identified, and the methodology for evaluating appropriate exposure scenarios is discussed.
Field-scale and watershed-scale measurement end points of most use in assessing the effects of stressors on the WQF are identified
and discussed. The product of this study is a conceptual model of how risks to the WQF of BHRE are produced and how the risk
and associated uncertainties can be quantified. 相似文献