全文获取类型
收费全文 | 810篇 |
免费 | 57篇 |
国内免费 | 42篇 |
专业分类
安全科学 | 107篇 |
废物处理 | 5篇 |
环保管理 | 313篇 |
综合类 | 222篇 |
基础理论 | 47篇 |
污染及防治 | 18篇 |
评价与监测 | 37篇 |
社会与环境 | 25篇 |
灾害及防治 | 135篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 19篇 |
2021年 | 25篇 |
2020年 | 16篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 16篇 |
2016年 | 10篇 |
2015年 | 19篇 |
2014年 | 27篇 |
2013年 | 39篇 |
2012年 | 39篇 |
2011年 | 42篇 |
2010年 | 28篇 |
2009年 | 34篇 |
2008年 | 40篇 |
2007年 | 62篇 |
2006年 | 40篇 |
2005年 | 49篇 |
2004年 | 44篇 |
2003年 | 30篇 |
2002年 | 22篇 |
2001年 | 29篇 |
2000年 | 21篇 |
1999年 | 19篇 |
1998年 | 18篇 |
1997年 | 20篇 |
1996年 | 21篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 17篇 |
1986年 | 2篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有909条查询结果,搜索用时 0 毫秒
581.
刘冰 《辽宁城乡环境科技》2013,(9):42-43
阐述了地源热泵的节能机理及优点,并以沈阳某办公区为例,计算供暖期、制冷期节省标准煤量,结果表明:使用地源热泵供暖、制冷比传统方式全年减少排放二氧化碳4898.9t,二氧化硫27.6t,地源热泵的使用将带来巨大的环保效益和良好的生活环境。 相似文献
582.
583.
轨道交通运行引起的场地振动实测研究现状 总被引:4,自引:0,他引:4
随着快速轨道交通的发展,轨道交通运行所带来的振动影响越来越严重,而已有的轨道交通运行引起的场地振动实测研究,大多集中在列车速度较低的情况下,已无法解决现行问题.本文通过对轨道交通运行引起的场地振动的现场测试进行评述,总结了目前该实测研究中存在的问题,提出尚需进一步研究的建议.今后的研究需综合分析各种因素对地面振动和地基... 相似文献
584.
丘陵地区工业污染源的大气影响预测,由于特殊的地理环境,大气扩散模式中最大地面浓度Cm及其距排气筒的距离Xm的烟轴He需修正。 相似文献
585.
Tiao J. Chang Choo B. Teoh 《Journal of the American Water Resources Association》1995,31(6):1001-1007
round water drought events were derived by taking a truncation level through the time series of daily ground water depth that are recorded elevation differences between the water table and land surface at a well site. Droughts of various truncation levels at 70, 80, 90, and 95 percent, were obtained, where a 70 percent truncation level means that 70 percent of ground water depth data are less than or equal to the truncated value. The conditional probability that a drought occurring at a certain truncation level will prolong and advance to that of the next higher level was estimated. The regionalization analysis was conducted assuming that conditional probabilities estimated at selected wells are regionalized variables. Contour lines of conditional probabilities for each truncation level were constructed to express their spatial variability in the region. Estimation errors associated with the regionalization were reasonably small. 相似文献
586.
膜电容去离子(membrane capacitive deionization, MCDI)技术具有的装置简单、易操作、易再生、成本低,无污染、节能等优势,使其成为一种新型的脱盐技术。为了提升MCDI的脱盐性能,将多个装置的进水串联,对每个装置单独加电来探究脱盐率,平均脱盐速率、单位能量脱盐量等指标对多级串联的影响。结果表明,在进水盐质量浓度、水力停留时间、电压等不同操作条件下,二、三级MCDI串联脱盐率都提高了约2、3倍,三级串联较二级串联的脱盐速率提升较小,但具有更高的能耗。综合比较,二级MCDI串联的脱盐性能更优,并获得了最佳的操作条件为1.5 g·L−1,0.375 min,1.2 V。在连续脱盐过程中,多级串联能够连续稳定的去除盐离子,并且具有较高的吸附容量,表明了连续脱盐的可行性。研究结果对多级MCDI脱盐工程化应用具有指导意义。 相似文献
587.
如何得到尽可能多的强地面运动参数是地震灾害调查中的一个重要问题。针对汶川大地震的情况,本文探讨用监控录像资料进行强地面运动参数估计的可能性。用陕西省汉中市宁强县宁强第一中学的监控录像资料推算,当地主震强地面运动的持续时间约为80~100s,强地面运动以较小的运动开始,到50s时达到峰值;用都江堰银行的监控录像估计,主震发生时当地的地面运动加速度至少为0.14g。 相似文献
588.
ABSTRACT This study examined the feasibility of extending the Accelerated Salt Transport (ASTRAN) method of groud water quality control to a complex, closed basin which is experiencing ground water quality degradation from irrigated agriculture (e.g., the Tulare Lake Basin in the Southern portion of the California Central Valley). A linear programming model was constructed and parametric analysis conducted which produced results with a “general appraisal” (or “level B”) degree of accuracy. The study concluded that a drainage water export drain is required in order to implement a long-term solution but that ground water degradation can be mitigated by a combination of the ASTRAN method and other measures even with existing entitlements and legal constraints. 相似文献
589.
Vikram M. Vyas Saichiu N. Tong Christopher Uchrin Panos G. Georgopoulos Gail P. Carter 《Journal of the American Water Resources Association》2004,40(1):187-195
ABSTRACT: The Kirkwood‐Cohansey aquifer has been identified as a critical source for meeting existing and expected water supply needs for southern New Jersey. Several contaminated sites exist in the region; their impact on the aquifer has to be evaluated using ground water flow and transport models. Ground water modeling depends on availability of measured hydrogeologic data (e.g., hydraulic conductivity, for parameterization of the modeling runs). However, field measurements of such critical data have inadequate spatial density, and their locations are often clustered. The goal of this study was to research, compile, and geocode existing data, then use geostatistics and advanced mapping methods to develop a map of horizontal hydraulic conductivity for the Kirkwood‐Cohansey aquifer. Spatial interpolation of horizontal hydraulic conductivity measurements was performed using the Bayesian Maximum Entropy (BME) Method implemented in the BMELib code library. This involved the integration of actual measurements with soft information on likely ranges of hydraulic conductivity at a given location to obtain estimate maps. The estimation error variance maps provide an insight into the uncertainty associated with the estimates, and indicate areas where more information on hydraulic conductivity is required. 相似文献
590.
Kathleen M. Clancy Aaron A. Jennings 《Journal of the American Water Resources Association》1988,24(2):307-316
ABSTRACT: Recent advances in mass transport modeling have made possible computation of the theoretical consequences of intricate multicomponent species interactions during ground water contamination events. Predictions such as strong chromatographic effects and induced downstream precipitations may have considerable impact on environmental analysis and regulation. Results of laboratory attempts to verify theoretical multicomponent transport predictions are discussed. Evidence presented here indicates that natural variability of soil properties make such verifications difficult. Although species interactions are easily confirmed, dramatic effects often exist only within small mathematical windows in strongly variable coefficient sets. Currently, the ability to generate multicomponent predictions apparently exceeds the ability to quantify the necessary, presumably deterministic, information required for real soils. 相似文献