全文获取类型
收费全文 | 5779篇 |
免费 | 419篇 |
国内免费 | 1817篇 |
专业分类
安全科学 | 528篇 |
废物处理 | 283篇 |
环保管理 | 419篇 |
综合类 | 3459篇 |
基础理论 | 944篇 |
环境理论 | 2篇 |
污染及防治 | 1427篇 |
评价与监测 | 295篇 |
社会与环境 | 273篇 |
灾害及防治 | 385篇 |
出版年
2024年 | 13篇 |
2023年 | 109篇 |
2022年 | 318篇 |
2021年 | 261篇 |
2020年 | 220篇 |
2019年 | 195篇 |
2018年 | 226篇 |
2017年 | 234篇 |
2016年 | 282篇 |
2015年 | 330篇 |
2014年 | 400篇 |
2013年 | 539篇 |
2012年 | 525篇 |
2011年 | 520篇 |
2010年 | 416篇 |
2009年 | 372篇 |
2008年 | 388篇 |
2007年 | 372篇 |
2006年 | 358篇 |
2005年 | 250篇 |
2004年 | 176篇 |
2003年 | 175篇 |
2002年 | 173篇 |
2001年 | 146篇 |
2000年 | 169篇 |
1999年 | 150篇 |
1998年 | 114篇 |
1997年 | 120篇 |
1996年 | 105篇 |
1995年 | 91篇 |
1994年 | 59篇 |
1993年 | 54篇 |
1992年 | 55篇 |
1991年 | 39篇 |
1990年 | 23篇 |
1989年 | 11篇 |
1988年 | 12篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1981年 | 4篇 |
1958年 | 1篇 |
排序方式: 共有8015条查询结果,搜索用时 109 毫秒
251.
绿色生产力是以"绿色"为核心价值的生产力。绿色文化是以生态科学和可持续发展理论作为思想基础的新兴文化,是倡导人与自然和谐相处的思想体系。绿色文化是发展绿色生产力的价值选择。绿色文化以科学技术为载体,发挥生产力功能。绿色文化作为价值观,指导管理、法律法规等,共同实现生产力绿色水平的提高。 相似文献
252.
近年来,废弃产品回收处理行业日益受到政府和社会各界的关注,而回收处理企业是实施回收处理活动的主体,相关法律、法规的出台对回收处理企业提出了更高的要求。本文在概括梳理相关法律、法规的基础上,初步建立了废弃产品回收处理企业环境绩效评价指标体系,为回收处理企业采用先进的技术工艺、降低环境负荷、加强职业健康监护和企业环境管理提供参考,以适应国家政策要求和行业发展的需要。 相似文献
253.
254.
应用Agilent 6890 plus 气相色谱仪(配有FID),把一根50 m×0.25 mm×0.5 μm PEG-20M毛细管色谱柱和一根100 m×0.25 mm×0.5 μm HP-1毛细管色谱柱串接,使得甲基叔丁基醚(MTBE)能和石脑油中其它组分完全分离,解决了石脑油中微量MTBE的测定难题.方法的标准偏差是0.20%,回收率为100%. 相似文献
255.
简要介绍了济南分公司油气回收装置、真空泵的工作原理以及安装与调试应注意的问题. 相似文献
256.
257.
258.
Seepage from Hg mine wastes and calcines contains high concentrations of mercury (Hg). Hg pollution is a major environmental
problem in areas with abandoned mercury mines and retorting units. This study evaluates factors, especially the hydrological and
sedimentary variables, governing temporal and spatial variation in levels and state of mercury in streams impacted by Hg contaminated
runo . Samples were taken during di erent flow regimes in theWanshan Hg mining area in Guizhou Province, China. In its headwaters
the sampled streams/rivers pass by several mine wastes and calcines with high concentration of Hg. Seepage causes serious Hg
contamination to the downstream area. Concentrations of Hg in water samples showed significant seasonal variations. Periods of
higher flow showed high concentrations of total Hg (THg) in water due to more particles being re-suspended and transported. The
concentrations of major anions (e.g., Cl??, F??, NO3?? and SO4
2??) were lower during higher flow due to dilution. Due to both sedimentation
of particles and dilution from tributaries the concentration of THg decreased from 2100 ng/L to background levels (< 50 ng/L) within
10 km distance downstream. Sedimentation is the main reason for the fast decrease of the concentration, it accounts for 69% and 60%
for higher flow and lower flow regimes respectively in the upper part of the stream. Speciation calculation of the dissolved Hg fraction
(DHg) (using Visual MINTEQ) showed that Hg(OH)2 associated with dissolved organic matter is the main form of Hg in dissolved
phase in surface waters in Wanshan (over 95%). 相似文献
259.
The effects of arbuscular mycorrhizal fungi (AMF) Glomus mosseae on the responses to elevated O3 in growth and nutrition of snap
bean (Phaseolus vulgaris L. cv Guangzhouyuan) were investigated. Exposure was conducted in growth chambers by using three O3
concentrations (20 (CF), 80 (CFO1) and 120 nL/L (CFO2); 8 hr/day for 75 days). Results showed that elevated O3 slightly impacted
overall mycorrhizal colonization, but significantly decreased the proportional frequency of hypha and increased the proportional
frequency of spores and vesicles, suggesting that O3 had significant effects on mycorrhizal structure. Elevated O3 significantly decreased
yield, dry mass and nutrient contents (N, P, K, Ca and Mg) in both non-mycorrhizal and mycorrhizal plants. However, significant
interactive effects were found in most variables due to that the reduction by O3 in the mycorrhizal plants was less than that in the
non-mycorrhizal plants. Additionally, AMF increased the concentrations of N, P, Ca, and Mg in shoot and root. It can be concluded
that AMF alleviated detrimental effects of increasing O3 on host plant through improving plant nutrition and growth. 相似文献
260.
Application of Ruditapes Philippinarum conglutination mud (RPM) for decolorizing synthetic dye solutions was studied. RPM showed good activity for decolorization of Methylene Blue, Crystal Violet, Malachite Green, and Ink Blue. The amount of the RPM had great effect on the decoloration rate of the dye solutions. However, the decoloration rate did not continue to increase when the amount of mud exceeded the optimum dose. The temperature of the dye solution had a remarkable effect on the decolorization rate of Ink Blue solution, but had little effect on the other three dye solutions. The initial pH of the dye solutions evidently affected the decolorization rate of Malachite Green solution, but had less effect on the other three. The decolorization rate of the dye solutions increased significantly with treatment time within 8 hr, but tended to be steady after 8 hr for Methylene Blue, Crystal Violet and Malachite Green solutions, and after 12 hr for Ink Blue solution. The decolorization efficiencies for the four dye solutions under the optimum conditions were all above 90%. Seventeen strains screened from RPM showed flocculation ability for kaolin clay suspension. Out of them, the flocculation rate of strain ZHT3-9 and strain ZHT4-13 were up to 88.14% and 86.01%, respectively. ZHT3-9 was studied, and its decolorization rate for Methylene Blue, Crystal Violet, and Malachite Green reached 90.02%, 89.21%, and 80.29%, respectively. By morphological, physiological and biochemical characteristics analysis and 16S rRNA sequencing, the strain ZHT3-9 was identified as Arthrobacter sp. 相似文献