全文获取类型
收费全文 | 193篇 |
免费 | 26篇 |
国内免费 | 48篇 |
专业分类
安全科学 | 35篇 |
废物处理 | 5篇 |
环保管理 | 23篇 |
综合类 | 106篇 |
基础理论 | 37篇 |
污染及防治 | 22篇 |
评价与监测 | 5篇 |
社会与环境 | 21篇 |
灾害及防治 | 13篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 14篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 14篇 |
2016年 | 10篇 |
2015年 | 14篇 |
2014年 | 12篇 |
2013年 | 10篇 |
2012年 | 11篇 |
2011年 | 13篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 16篇 |
2007年 | 15篇 |
2006年 | 15篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1993年 | 4篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有267条查询结果,搜索用时 46 毫秒
1.
石灰石-石灰乳二段中和法处理矿山酸性废水 总被引:12,自引:0,他引:12
分析了处理含重金属离子矿山酸性废水的处理工艺。通过实例说明石灰石-石灰乳二段中和法与传统的石灰乳中和工艺相比,有较大的优越性,可以降低处理成本和减少沉渣的产生量。 相似文献
2.
三步沉淀全循环法处理焙烧—氰化工艺中含氰废水的应用 总被引:1,自引:0,他引:1
厚春华 《辽宁城乡环境科技》2007,27(3):49-51
辽宁新都黄金有限责任公司成功应用三步沉淀全循环法处理焙烧一氰化工艺中含氰废水,该处理工艺不但可回收有价金属,有效地利用废水中的氰化物,且能够提高金、银的氰化浸出率,实现了闭路全循环含氰废水零排放的目的,其环境效益经济效益和社会效益非常显著。 相似文献
3.
中国东南沿海中生代火山作用基本特征 总被引:3,自引:0,他引:3
中国东南沿海自晚侏罗世到白垩纪火山活动分为二期、四个旋回,在空间上有迁移性,在时间上与侵入活动呈交替式演变。建立火山碎屑流等五种岩相模式,岩浆爆发占主导地位,同时存在蒸气岩浆爆发。确定破火山口、火山穹隆和锥火山为火山构造基本类型。由火山作用与区域构造作用、沉积作用控制形成火山沉积洼地、火山构造洼地和火山构造隆起。提出不同类型火山构造组合形式和相互演化关系。火山岩系列属高钾钙碱系列,晚期则具双模式性质。它们的地球化学型式兼具大陆边缘和大陆板内双重特性。 相似文献
4.
Environmental heterogeneity is increasingly being used to select conservation areas that will provide for future biodiversity under a variety of climate scenarios. This approach, termed conserving nature's stage (CNS), assumes environmental features respond to climate change more slowly than biological communities, but will CNS be effective if the stage were to change as rapidly as the climate? We tested the effectiveness of using CNS to select sites in salt marshes for conservation in coastal Georgia (U.S.A.), where environmental features will change rapidly as sea level rises. We calculated species diversity based on distributions of 7 bird species with a variety of niches in Georgia salt marshes. Environmental heterogeneity was assessed across six landscape gradients (e.g., elevation, salinity, and patch area). We used 2 approaches to select sites with high environmental heterogeneity: site complementarity (environmental diversity [ED]) and local environmental heterogeneity (environmental richness [ER]). Sites selected based on ER predicted present‐day species diversity better than randomly selected sites (up to an 8.1% improvement), were resilient to areal loss from SLR (1.0% average areal loss by 2050 compared with 0.9% loss of randomly selected sites), and provided habitat to a threatened species (0.63 average occupancy compared with 0.6 average occupancy of randomly selected sites). Sites selected based on ED predicted species diversity no better or worse than random and were not resilient to SLR (2.9% average areal loss by 2050). Despite the discrepancy between the 2 approaches, CNS is a viable strategy for conservation site selection in salt marshes because the ER approach was successful. It has potential for application in other coastal areas where SLR will affect environmental features, but its performance may depend on the magnitude of geological changes caused by SLR. Our results indicate that conservation planners that had heretofore excluded low‐lying coasts from CNS planning could include coastal ecosystems in regional conservation strategies. 相似文献
5.
Archambault DJ Li X Foster KR Jack TR 《Environmental monitoring and assessment》2006,115(1-3):509-530
Ethephon, which releases ethylene within plant tissues after application, was chosen to perform assessments of the relative sensitivity of crops to ethylene and to determine which stages of plant development were most sensitive. The species chosen were: barley, wheat, oats, canola and field pea, all of which are important crops in the province of Alberta, Canada. Plants were treated with ethephon at one of 7 different stages. Plants were assessed for their vegetative and reproductive growth, including height, biomass, yield and seed quality. Visual symptoms were photographed and documented to compare them with symptoms caused by ethylene applied as a gas. It was concluded that in barley, wheat and canola the late vegetative and early reproductive stages were most sensitive, at least when sensitivity was defined as reductions in yield and quality. As for field pea, ethephon had no effect on yield but did cause increased numbers of pods, which in certain conditions could lead to increased yields. Significant effects on vegetative growth were only observed in the early vegetative stages of development but with no effects on yield. The screening protocol successfully identified sensitive cultivars and growth stages for further investigation of the effects of ethylene exposure. 相似文献
6.
我国冬小麦霜冻灾害致灾因子危险度评价——基于作物生育阶段气象指标 总被引:3,自引:1,他引:2
霜冻是一种威胁农业生产的气象灾害,对其致灾因子危险度的研究,可为大尺度的作物霜冻灾害区划及农业保险提供依据。根据作物生长发育的阶段性原理,以全国751个气象台站56年的逐日最低气温资料以及作物生育期资料为基础,统计得到冬小麦各个生育阶段不同灾害等级(轻霜冻、中霜冻、重霜冻)的年霜冻日数,并计算出冬小麦全生育期内不同等级霜冻的发生概率,基于以上两项指标对冬小麦霜冻致灾因子危险度做出评价。结果表明,研究期内重霜冻年霜日最大值为129d,而轻霜冻和中霜冻霜日最大值分别为23 d和19 d,冬小麦受重霜冻危害时间较长;冬小麦霜冻的频发区、多发区、少发区从北向南依次分布,随着霜冻等级增加,频发区的面积差异不大,但多发区的面积减小、少发区面积增大;冬小麦霜冻灾害危险度等级最低的地区主要分布在低纬度的几个省份,如海南、广东、广西、云南等,危险度等级最高的地区集中在青藏高原地区。 相似文献
7.
为了有效的把国家可再生能源规划分阶段的落实到各个省市,做好二者之间衔接工作,研究考虑了我国在从发展中国家过渡到中等发达国家时所需要考虑的如何平衡公平与效率之阀关系的问题,结合中国可再生能源发展实际特征,提出一种基于行业增长曲线的可再生能源阶段目标分解模型.模型首先求解出中国不同的可再生能源行业的增长曲线.然后给出可再生能源发展阶段目标函数.结合区域发展规划,给出了各省的阶段目标,为了验证该模型的正确性,以风电、水电和太阳发电为代表能源,结合国家可再生能源整体规划和资源需求分布状况,分阶段提出了各省域的可再生能源发展目标.目标分解参照两个原则(1)可分解原则.国家总量目标可以根据一定的标准在不同地区、部门和行业进行分解,由全社会共同完成发展目标.(2)公平性和区域差异的原则.考虑资源禀赋和社会经济发展水平差距,各地总量目标有所区别.研究对于可再生能源规划的整体实施和监管具有一定的借鉴意义. 相似文献
8.
Irrigation Water Allocation Using an Inexact Two‐Stage Quadratic Programming with Fuzzy Input under Climate Change
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mo Li Ping Guo Vijay P. Singh Jie Zhao 《Journal of the American Water Resources Association》2016,52(3):667-684
Agricultural irrigation accounts for nearly 70% of the total water use around the world. Uncertainties and climate change together exacerbate the complexity of optimal allocation of water resources for irrigation. An interval‐fuzzy two‐stage stochastic quadratic programming model is developed for determining the plans for water allocation for irrigation with maximum benefits. The model is shown to be applicable when inputs are expressed as discrete, fuzzy or random. In order to reflect the effect of marginal utility on benefit and cost, the model can also deal with nonlinearities in the objective function. Results from applying the model to a case study in the middle reaches of the Heihe River basin, China, show schemes for water allocation for irrigation of different crops in every month of the crop growth period under various flow levels are effective for achieving high economic benefits. Different climate change scenarios are used to analyze the impact of changing water requirement and water availability on irrigation water allocation. The proposed model can aid the decision maker in formulating desired irrigation water management policies in the wake of uncertainties and changing environment. 相似文献
9.
James D. Salierno Melissa Lopes Michelle Rivera 《Journal of environmental science and health. Part. B》2016,51(10):695-702
The objective of this study was to evaluate the effects of early life stage triclosan (5-chloro-2-(2,4, dichlorophenoxy)phenol, TCS) exposure on hatching, development, and survival in the fathead minnow, Pimephales promelas. Embryonic minnows were exposed to TCS (50 and 100 µg L?1) for 10 days followed by 6 weeks depuration. Mortality and morphological deformities were recorded and quantified during exposure and at the end of depuration. No significant effects on embryonic survival, time to reach the eyed stage, or hatching were found. However, at the conclusion of the depuration period, survival was significantly reduced in TCS exposed fish depending on the concentration. Visual inspection of the exposed fish suggests that mortality is related to spinal deformities, emaciation, and reduced foraging ability. Triclosan exhibits deleterious effects in fish at lower concentrations over longer durations than previously reported. Further, mortality in exposed fish 6 weeks after exposure demonstrates the need for various exposure assays to evaluate effects of TCS. 相似文献
10.
根据内抽外压式集烟尘器专利研制了一个内抽外压式集尘器,并在井下进行实验。经过3种方法测试均收到预期的的效果,司机工作区达到了国家卫生要求,由于采用外筒压风,防止了瓦斯积聚避免瓦斯爆炸。应用离散颗粒模型模拟了内抽外压式集尘器内气相流场和粉尘颗粒的运动,该集尘器不仅把矿井巷道中细微可呼吸粉尘吸收到除尘器中,又能防止了瓦斯积聚。数值模拟与实验结果的一致性表明:把内抽外压式集尘器放置在掘进机前方,由于粉尘在气流的携带下运动使掘进机司机在矿井巷道中的工作环境得到改善,减少矿工患尘肺病的概率,开发了井下集尘的新工艺、新设备。 相似文献