首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   540篇
  免费   32篇
  国内免费   226篇
安全科学   42篇
废物处理   36篇
环保管理   45篇
综合类   314篇
基础理论   111篇
污染及防治   174篇
评价与监测   27篇
社会与环境   19篇
灾害及防治   30篇
  2023年   15篇
  2022年   25篇
  2021年   24篇
  2020年   25篇
  2019年   21篇
  2018年   25篇
  2017年   28篇
  2016年   28篇
  2015年   46篇
  2014年   42篇
  2013年   63篇
  2012年   56篇
  2011年   49篇
  2010年   38篇
  2009年   32篇
  2008年   37篇
  2007年   50篇
  2006年   30篇
  2005年   16篇
  2004年   10篇
  2003年   14篇
  2002年   23篇
  2001年   9篇
  2000年   11篇
  1999年   17篇
  1998年   10篇
  1997年   7篇
  1996年   9篇
  1995年   11篇
  1994年   6篇
  1993年   8篇
  1992年   7篇
  1991年   1篇
  1984年   1篇
  1982年   2篇
  1981年   2篇
排序方式: 共有798条查询结果,搜索用时 421 毫秒
601.
剖析了国企安全生产中发挥党组织作用的现实差距,提出了安全生产中发挥党组织作用的路径措施:深化政治建设提升引领力,抓好有效覆盖提升组织力,促进深度融合提升推动力,加强群团作用提升凝聚力,强化监督考评提升驱动力。充分发挥党组织作用,使"根"从基层扎牢、"魂"从堡垒筑强,就能本固基稳,扛起安全生产"泰山之重"的责任,引领保障企业高质量发展和建设世界一流企业行稳致远。  相似文献   
602.
近年来,SiC材料作为一种新型的柴油车尾气颗粒物过滤材料获得了迅速发展,正逐步取代目前广泛应用的堇青石多孔陶瓷材料.结合堇青石和SiC过滤材料的性能特点,重点概述了2种SiC改性过滤材料(重结晶SiC.RSiC和硅结合SiC,Si-SiC)的研究和应用进展,并介绍了SiC颗粒物过滤器的市场现状和发展前景.  相似文献   
603.
Obtaining and analyzing the specific inherent optical properties (SIOPs) of water bodies is necessary for bio-optical model development and remote sensing-based water quality retrievals and, further, for related ecological studies of aquatic ecosystems. This study aimed to measure and analyze the specific absorption and backscattering coefficients of the main water constituents in Poyang Lake, China. The specific absorption and/or backscattering coefficients of the main water constituents at 85 sampling sites (47 in 2010 and 38 in 2011) were measured and analyzed as follows: (1) the concentrations of chlorophyll a (C CHL), suspended particulate matter (C SPM) (including suspended particulate inorganic matter (C SPIM) and suspended particulate organic matter (C SPOM)), and the absorption coefficients of total particulate (a p), phytoplankton (a ph), and non-pigment particulate (a d) were measured in the laboratory; (2) the total backscattering coefficients at six wavelengths of 420, 442, 470, 510, 590, and 700 nm, including the contribution of pure water, were measured in the field with a HydroScat-6 backscattering sensor, and the backscattering coefficients without the contribution of pure water (b b) were then derived by subtracting the backscattering coefficients of pure water from the total backscattering coefficients; (3) the specific absorption coefficients of total particulate ( $ a_{\mathrm{p}}^{ * } $ ), phytoplankton ( $ {a_{{\mathrm{ph}}}}^{ * } $ ), and non-pigment particulate ( $ a_{\mathrm{d}}^{ * } $ ) were calculated by dividing a p, a ph, and a d by C SPM, C CHL, and C SPIM, respectively, while the specific backscattering coefficients of total suspended particulate matter ( $ b_{\mathrm{b}}^{ * } $ ) were calculated by dividing b b by C SPM; and (4) the $ {a_{{\mathrm{ph}}}}^{ * } $ , $ a_{\mathrm{d}}^{ * } $ , $ a_{\mathrm{p}}^{ * } $ and $ b_{\mathrm{b}}^{ * } $ of the remaining samples (46 in 2010 and 36 in 2011) were visualized and analyzed, and their relations to C CHL, C SPIM or C SPM were studied, respectively. The main results are summarized as follows: (1) the $ {a_{{\mathrm{ph}}}}^{ * } $ values at 440 nm were 0.0367–0.7203 m2?mg?1 with a mean of 0.1623?±?0.1426 m2?mg?1 in 2010 and 0.0319–0.7735 m2?mg?1 with a mean of 0.3145?±?0.1961 m2?mg?1 in 2011; there existed significant, negative, and moderate correlations between $ {a_{{\mathrm{ph}}}}^{ * } $ and C CHL at 400–700 nm in 2010 and 2011 (p?<?0.05); (2) The $ a_{\mathrm{d}}^{ * } $ values at 440 nm were 0.0672–0.2043 m2?g?1 with a mean of 0.1022?±?0.0326 m2?g?1 in 2010 and 0.0559–0.1347 m2?g?1 with a mean of 0.0953?±?0.0196 m2?g?1 in 2011; there existed negative correlations between $ a_{\mathrm{d}}^{ * } $ and C SPIM, while the correlations showed overall decreasing and increasing trends before and after around 575 nm with increasing wavelengths, respectively; (3) The $ a_{\mathrm{p}}^{ * } $ values at 440 nm were 0.0690–0.1929 m2?g?1 with a mean of 0.1036?±?0.0298 m2?g?1 in 2010 and 0.0571–0.1321 m2?g?1 with a mean of 0.1014?±?0.0191 m2?g?1 in 2011, and the negative correlations between $ a_{\mathrm{p}}^{ * } $ and C SPM were found in both years; (4) The $ b_{\mathrm{b}}^{ * } $ at the six wavelengths generally decreased with increasing wavelengths, while the $ b_{\mathrm{b}}^{ * } $ values at 420 nm were lower than those at 442 nm for some samples; the correlation between $ b_{\mathrm{b}}^{ * } $ and C SPM increased with increasing wavelength. Such results can only represent the SIOPs during the sampling time periods, and more measurements and analyses considering different seasons need to be carried out in the future to comprehensively understand the SIOPs of Poyang Lake.  相似文献   
604.
Dissolved inorganic tin (DISn) and its spatial variation were examined in Bohai Bay seawaters to understand the DISn behavior and pollution in this area. DISn concentration gradually increased with the distance from the coast and showed a slight decrease with the increasing depth from surface water, suggesting the scavenged behavior of tin with an atmospheric input to surface water. Besides, the higher DISn values also were found near the Haihe Estuary inferring that the riverine input was a source of DISn. Based on the data in this study, a preliminary estimate of the tin budget via riverine input and atmospheric deposition has been established. According to our estimate, about 2 × 106 and 8.47 × 105 g/year of tin reach Bohai Bay via rivers and atmosphere. Environmental factors such as suspended particulate material, salinity, total organic matter, pH, nutrients, and phytoplankton had the important influences on DISn distribution. Among them, the negative correlation between DISn and phytoplankton at most stations might indicate the biological uptake of tin.  相似文献   
605.
陕西省引汉济渭工程属于跨流域大型水利工程,5个单元工程呈线状跨越构造剥蚀山地和断陷盆地,工程地质性质差异大,易发生地质灾害。实地调查地质灾害点共72处,其中滑坡66处,崩塌3处,泥石流3处。现状评估认为地质灾害危险性中等13处,其余59处均为危险性小。预测评估认为工程本身可能遭受31处地质灾害威胁,危险性小28处,危险性中等3处;工程建设可能加剧地质灾害39处,危险性小36处,危险性中等3处;工程建设可能引发地质灾害30处,危险性小15处,危险性中等15处。综合评估工程主要位于危险性小的区段,受地质灾害危害不大,风险较低。  相似文献   
606.
To investigate nitrous acid(HONO) levels and potential HONO sources above crop rotation fields. The HONO fluxes were measured by the aerodynamic gradient(AG) method from 14 December 2019 to 2 January 2020 over an agricultural field in the Huaihe River Basin. The ambient HONO levels were measured at two different heights(0.15 and 1.5 m), showing a typical diurnal cycle with low daytime levels and high nighttime levels. The upward HONO fluxes were mostly observed during the day, whereas deposition...  相似文献   
607.
人类肠道菌群是耐药基因(antibiotic resistance genes,ARGs)的"储存库",且与人体健康密切相关。目前,抗生素的滥用严重,进一步加剧了耐药基因的传播和扩散。细菌耐药问题严重影响人体健康、食品安全和生态安全,携带耐药基因的致病菌对临床治疗造成巨大威胁。本文结合国内外研究进展,在总结人体肠道耐药基因组研究方法的基础上,探讨了肠道耐药基因的组成、来源、传播和进化,并对未来研究进行了展望,旨在促进公众对肠道耐药基因的认知,并为抗生素的合理使用提供理论支持。  相似文献   
608.
ABSTRACT

The “green” production of bitumen has raised increasing interest in recent years to reduce the environmental, energy-related and petro-based concerns. Bio-oil, prepared by biomass pyrolysis, can be used as a substitute for petro-based bitumen in bitumen or bitumen-based coatings, for its similar properties of good adhesion and anti-corrosion characteristics as bitumen. Although biomass is a renewable and widespread chemical resource, its high-valued utilization is still difficult. Several studies have qualitatively demonstrated the use of bio-bitumen in practical applications. The present study investigates that adding some bio-oil to traditional bitumen to form a bio-bitumen could help improve the properties of traditional bitumen. Bio-bitumen was prepared from biomass pyrolysis oil and applied to self-adhesive and doped hot-melt sheets. Results of physical properties demonstrate that bio-bitumen is a potential substitute in bitumen coating sheet.

Implications: This paper is intended to verify the effect of pyrolyzed bio-oil from wheat straw on the performance of bitumen, as well as the feasibility of application in the coating sheet. Up to now, the research on bio-bitumen is mainly in pavement bitumen. In the present research, bio-bitumen was applied to the coating sheet in different proportions. Interestingly, the prepared coating sheet exhibited higher adhesion. Other performances, such as temperature stability, mechanical strength and temperature flexibility of coating sheet showed improvement in the presence of bio-oil, which indicated the suitability of bio-oil in coating sheet bitumen.  相似文献   
609.
建立微库仑滴定法测定水质中可吸附有机卤素AOX的方法,考察3种活性炭柱对于空白的影响。实验结果表明,AOX的检出限为2.19μg/L,相对标准偏差为2.80%,纯水中高、中、低加标回收率在92.5%~107%,新疆棉浆粕企业废水中加标回收率为96.0%~101%。实验室空白也只有新购开封的耶拿原装活性炭小柱能满足标准要求的空白值(<30μg/L)。  相似文献   
610.
Environmental Science and Pollution Research - Cadmium (Cd) pollution threatens agricultural security worldwide. This study tested the efficacy of priming chemicals to decrease Cd uptake by tobacco...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号