全文获取类型
收费全文 | 6292篇 |
免费 | 894篇 |
国内免费 | 3365篇 |
专业分类
安全科学 | 357篇 |
废物处理 | 239篇 |
环保管理 | 1040篇 |
综合类 | 6174篇 |
基础理论 | 867篇 |
环境理论 | 4篇 |
污染及防治 | 875篇 |
评价与监测 | 495篇 |
社会与环境 | 465篇 |
灾害及防治 | 35篇 |
出版年
2024年 | 99篇 |
2023年 | 306篇 |
2022年 | 485篇 |
2021年 | 455篇 |
2020年 | 451篇 |
2019年 | 406篇 |
2018年 | 394篇 |
2017年 | 405篇 |
2016年 | 458篇 |
2015年 | 522篇 |
2014年 | 549篇 |
2013年 | 725篇 |
2012年 | 763篇 |
2011年 | 722篇 |
2010年 | 487篇 |
2009年 | 414篇 |
2008年 | 361篇 |
2007年 | 410篇 |
2006年 | 394篇 |
2005年 | 269篇 |
2004年 | 212篇 |
2003年 | 205篇 |
2002年 | 173篇 |
2001年 | 151篇 |
2000年 | 131篇 |
1999年 | 98篇 |
1998年 | 105篇 |
1997年 | 81篇 |
1996年 | 72篇 |
1995年 | 45篇 |
1994年 | 55篇 |
1993年 | 37篇 |
1992年 | 31篇 |
1991年 | 16篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
941.
942.
Minimum relative entropy (MRE) and Tikhonov regularization (TR) were compared by Neupauer et al. [Water Resour. Res. 36 (2000) 2469] on the basis of an example plume source reconstruction problem originally proposed by Skaggs and Kabala [Water Resour. Res. 30 (1994) 71] and a boxcar-like function. Although Neupauer et al. [Water Resour. Res. 36 (2000) 2469] were careful in their conclusions to note the basis of these comparisons, we show that TR does not perform well on problems in which delta-like sources are convolved with diffuse-groundwater contamination response functions, particularly in the presence of noise. We also show that it is relatively easy to estimate an appropriate value for epsilon, the hyperparameter needed in the minimum relative entropy solution for the inverse problem in the presence of noise. This can be estimated in a variety of ways, including estimation from the data themselves, analysis of data residuals, and a rigorous approach using the real cepstrum and the Akaike Information Criterion (AIC). Regardless of the approach chosen, for the sample problem reported herein, excellent resolution of multiple delta-like spikes is produced from MRE from noisy, diffuse data. The usefulness of MRE for noisy inverse problems has been demonstrated. 相似文献
943.
介绍了一种电除尘器脉冲供电的基本原理及其在锌沸腾炉电除尘器上的应用试验情况。结果表明,在基本保持同一工况条件下,脉冲供电比直流供电降低出口烟气含尘浓度50.4%~79.6%;脉冲供电能改善电除尘器运行性能,提高电除尘器改善系数达1.32;脉冲供电运行安全可靠。 相似文献
944.
研究了操作参数对活性炭固定床处理有机废气的影响。温度升高,吸附容量下降。湿度的存在会减少活性炭对有机物的吸附容量。适当的操作气速为0.1-0.5m/s,在此范围内,气速与压降在对数坐标上呈线性关系。 相似文献
945.
946.
947.
炭素焙烧炉沥青烟净化处理 总被引:1,自引:0,他引:1
采用干式静电除尘技术,对炭素焙烧炉排放的含有烟尘、沥青烟的工业废气进行处理,达到既能高效净化有害气体,又能降低资金投入。处理后的各项指标为:烟尘排放浓度=20.0mg/m3,沥青烟排放浓度=14.2mg/m3,苯并(a)芘排放浓度=0.054×10-3mg/m3,所有污染物均达到排放标准。 相似文献
948.
按GB11890—89顶空气相色谱法分析苯系物时,发现重复性和分割水平样品平行性较差,经仔细分析,是由于使用普通玻璃注射器造成的。为避免此类误差,建议顶空气相色谱法分析时,使用带特氟龙顶端推杆的气密性注射器。 相似文献
949.
We designed a microcosm experiment to assess the influence of inoculation with Eisenia foetida earthworms and the establishment of an Avena sativa cover crop on biological (enzyme activities and labile carbon fractions) soil quality indicators in a soil treated with a composted organic residue, and to determine the contribution of these treatments to carbon dioxide emissions from the soil to the atmosphere of the microcosm. The microcosms were incubated for 53 days under 28 °C/18 °C day/night temperatures. The addition of earthworms and the planting of A. sativa increased dehydrogenase activity of compost amended soil by about 44% after 23 days of incubation. The metabolic potential, calculated as the ratio dehydrogenase activity/water soluble C, was higher in the compost amended soil planted with A. sativa. The highest total amount of CO2–C evolved occurred in the soil treated with composted residue and earthworms (about 40% of the total amount of CO2 evolved came from earthworm activity). The planting of A. sativa increased the decomposition rate constant of organic matter in the amended soil but decreased the potentially mineralizable C pool. In conclusion, the establishment of an A. sativa cover crop and the addition of E. foetida to a degraded agricultural soil treated with composted residue were effective treatments for improving the biological and biochemical quality and the metabolic potential of the soil. 相似文献
950.