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   894篇
  免费   87篇
  国内免费   215篇
安全科学   80篇
废物处理   59篇
环保管理   68篇
综合类   476篇
基础理论   164篇
环境理论   1篇
污染及防治   211篇
评价与监测   71篇
社会与环境   34篇
灾害及防治   32篇
  2024年   3篇
  2023年   21篇
  2022年   63篇
  2021年   62篇
  2020年   58篇
  2019年   56篇
  2018年   41篇
  2017年   61篇
  2016年   50篇
  2015年   61篇
  2014年   55篇
  2013年   89篇
  2012年   68篇
  2011年   69篇
  2010年   54篇
  2009年   55篇
  2008年   53篇
  2007年   43篇
  2006年   38篇
  2005年   36篇
  2004年   36篇
  2003年   32篇
  2002年   26篇
  2001年   12篇
  2000年   8篇
  1999年   8篇
  1998年   5篇
  1997年   3篇
  1996年   1篇
  1995年   2篇
  1994年   3篇
  1993年   2篇
  1992年   3篇
  1991年   4篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   3篇
  1985年   2篇
  1972年   1篇
  1971年   1篇
  1967年   1篇
  1958年   1篇
排序方式: 共有1196条查询结果,搜索用时 187 毫秒
991.
目前中国在环境监测市场化发展方面仍处于探索阶段,在政策体系、法律体系和监管制度等方面还存在许多问题,国际上一些发达国家在环境监测的市场化发展方面已有诸多成功经验,可供中国参考。研究主要以日本环境监测市场化运行模式为例,分析日本成功经验,并对中国环境监测市场化发展提出针对性建议,以供相关政府部门参考和借鉴。  相似文献   
992.
ABSTRACT

Abandoned industrial sites and mines may constitute possible hazards for surrounding environment due to the presence of toxic compounds that may contaminate soils and waters. The possibility to remove metal contaminants, specifically nickel (Ni), by means of fungi was presented exploiting a set of fungal strains isolated from a Ligurian dismissed mine. The achieved results demonstrate the high Ni(II) tolerance, up to 500 mg Ni l?1, and removal capability of a Trichoderma harzianum strain. This latter hyperaccumulates up to 11,000 mg Ni kg?1, suggesting its possible use in a bioremediation protocol able to provide a sustainable reclamation of broad contaminated areas.  相似文献   
993.
With the development of ultra-high-voltage direct-current (UHVDC) transmission technology and increase in transmission voltage, the issue of environmental static electric field (SEF) pollution is standing out and its possible health effects have caused much public attention. In this study, the effects of chronic exposure to SEF on reproductive capacity of male mice were investigated. Twenty Institute of Cancer Research (ICR) mice were exposed to SEF (56.3 ± 1.4 kV/m, 49 days) generated by a high-voltage device. Several biological end points related to spermatogenesis and testicular function were evaluated, including reproductive organ coefficients, sperm motility and morphology, serum testosterone level, and testicular histology. No significant differences were found between the SEF-exposed and sham-exposed groups at the end of the exposure period. However, further observation through transmission electron microscopy revealed cristae losses in mitochondria of spermatogenic cells after SEF exposure. Nevertheless, the mitochondria injury did not affect sperm motility, which might be explained from the perspective of energy supply. That is, most of the energy required for sperm movement is generated by glycolysis which occurs in the cytoplasm rather than oxidative phosphorylation which occurs in mitochondria. In conclusion, this study indicates that exposure to SEF (56.3 ± 1.4 kV/m, 49 days) has limited effects on male reproductive capacity.  相似文献   
994.

Given their voluminous application, significant amounts of fluoroquinolones are discharged into the environment through wastewater effluent. Adsorption has been shown to be a critical process controlling the environmental behaviors of fluoroquinolones. Competition between ofloxacin (OFL) and naphthalene (NAP)/bisphenol A (BPA) and their adsorption on activated carbon (AC), graphite (GP), and humic acid (HA) were investigated. The suppressed adsorption of OFL was observed on AC and GP, but not on HA, by NAP or BPA. Moreover, for AC, the competition by NAP was slightly stronger than that by BPA. However, for GP, the competition with BPA was higher than that with NAP. These observations indicate that competitive adsorption of OFL with respect to NAP/BPA depends on the degree of overlap of adsorption sites, as interpreted by the following: (i) AC can provide overlapping adsorption sites for OFL, BPA, and NAP, which include non-specific adsorption sites, such as hydrophobic sites, π-π interactions, and micropore filling; (ii) π-π interactions and hydrogen bonding might be responsible for the strong competitive adsorption between BPA and OFL on GP; and (iii) OFL adsorbs on HA through specific adsorption force—electrostatic attraction, with which NAP and BPA cannot compete.

  相似文献   
995.
Environmental Science and Pollution Research - Paenibacillus species isolated from a variety of natural sources have shown to be important glycoside hydrolases producers. These enzymes play a key...  相似文献   
996.
在这个较广泛的关于单个和多组分混合药物活性化合物影响研究的第一部分,作者使用了Microtox?测试系统详细分析了10种广泛使用的人用和兽用药活性化合物对生物荧光细菌Aliivibrio fischeri的影响。实验结果表明大多数受试化合物具有中度毒性。对比实验得到的50%抑制浓度和定量构效关系模型预测的结果表明,大多数受试药物活性化合物与极性麻醉型化合物对A. fischeri的行为类似(似乎只有抗生素金霉素有特定的作用机制)。将实验结果与其他不属预定目标的生物急性毒性数据集进行比较表明,一般而言A . fischeri较其他水生物种敏感。然而,根据全球化学品统一分类和标签制度,大部分受调查的化学物质可归为水生生态系统中有害或无毒的化合物。最后,基于欧盟水体中测量的环境浓度第95百分位数和各种水生生物的急性毒性数据的比较,可以认为当受试药物活性化合物作为单一化合物进行评估的时候,不存在水生生物风险。
精选自Valeria Di Nica, Sara Villa, Antonio Finizio. Toxicity of individual pharmaceuticals and their mixtures to Aliivibrio fischeri: experimental results for single compounds and considerations of their mechanisms of action and potential acute effects on aquatic organisms. Environmental Toxicology and Chemistry: Volume 36, Issue 3, pages 807–814, July 2017. DOI: 10.1002/etc.3568
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3568/full
  相似文献   
997.
本文对国内生活生产类产品VOCs含量限值的国家标准、地方标准、行业标准以及中国香港、欧美等发达地区精细化的生活生产类产品VOCs含量限值法规和标准做了比较全面的综述,并从产品限值种类以及限值要求两个方面进行了对比研究和分析,提出了我国生产生活类产品VOCs 含量限值法规标准制定建议。笔者认为,应借鉴发达国家成功的生活生产类产品VOCs含量限值法规及标准制定经验,从做好标准和产品技术要求衔接、建立区域协同制定标准模式、结合经济因素或环境空气质量,分步推进相关标准制定和发布等方面入手,建立符合实际国情的产品种类较为全面、标准要求较高的生产生活类产品VOCs含量限值法规与标准体系,尤其是生活消费品方面,减少直接与人体接触的生活消费品VOCs排放。  相似文献   
998.
针对电网电压发生骤升故障时造成的电网不稳定运行,在双馈机组转子侧加入Crowbar保护电路,增加双馈风电系统高电压穿越的能力。通过建立电网电压骤升时双馈风电机组投入Crowbar保护电路后的数学模型,并从磁链角度推导出转子侧暂态电流及其最大估算值,根据短路电流和直流侧母线耐受电压的大小,确定Crowbar电路串联的电阻值、切入和退出时间,加速系统暂态电流的衰减,实现双馈系统的高电压穿越。Matlab/Simulink仿真结果表明:控制方案增强了双馈发电系统稳定运行的可靠性,并提高了双馈风力发电系统的高电压穿越能力。  相似文献   
999.
近几十年来,我国西南喀斯特地区生态环境退化严重,石漠化面积迅速扩大,林地覆盖率急剧下降,成为制约我国西部大开发生态建设中不可回避的重要科学问题,严重影响了西南地区社会、经济的可持续发展。喀斯特地区土层薄且侵蚀严重,土壤中的有机碳和营养盐主要来自地表枯枝落叶层的分解及累积。在气候变暖、陆地生态系统土壤温度升高、土壤有机碳急速流失和土壤质量退化的背景下,分析不同林下凋落物量和降解动态以及土壤有机碳库积累差异,揭示西南喀斯特地区不同林地凋落物归还量及其对土壤碳库积累的贡献具有极其重要的意义,将为喀斯特地区林地恢复重建和石漠化遏制工作提供科研依据。  相似文献   
1000.
Xiao D  Pan B  Wu M  Liu Y  Zhang D  Peng H 《Chemosphere》2012,86(2):183-189
The degradation intermediates of phenanthrene (PHE) may have increased health risks to organisms than PHE. Therefore, environmental fate and risk assessment studies should take into considerations of PHE degradation products. This study compared the sorption properties of PHE and its degradation intermediates, 9,10-phenanthrenequinone (PQN) and 9-phenanthrol (PTR) in soils, sediments and soil components. A relationship between organic carbon content (fOC) and single-point sorption coefficient (log Kd) was observed for all three chemicals in 10 soils/sediments. The large intercept in the log fOC − log Kd regression for PTR indicated that inorganic fractions control PTR sorption in soils/sediments. No relationship between specific surface area and Kd was observed. This result indicated that determination of surface area based on gas sorption could not identify surface properties for PHE, PQN, and PTR sorption and thus provide limit information on sorption mechanisms. The high sorption and strong nonlinearity (low n values) of PTR in comparison to PHE suggested that the mobility of PTR could be lower than PHE. Increased mobility of PQN compared with PHE may be expected in soils/sediments because of PQN lower sorption. The varied sorption properties of the three chemicals suggested that their environmental risks should be assessed differently.  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