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   3077篇
  免费   87篇
  国内免费   184篇
安全科学   142篇
废物处理   15篇
环保管理   747篇
综合类   1253篇
基础理论   199篇
污染及防治   269篇
评价与监测   581篇
社会与环境   107篇
灾害及防治   35篇
  2024年   4篇
  2023年   42篇
  2022年   45篇
  2021年   69篇
  2020年   93篇
  2019年   48篇
  2018年   48篇
  2017年   83篇
  2016年   106篇
  2015年   119篇
  2014年   137篇
  2013年   150篇
  2012年   126篇
  2011年   235篇
  2010年   85篇
  2009年   229篇
  2008年   196篇
  2007年   196篇
  2006年   148篇
  2005年   124篇
  2004年   115篇
  2003年   115篇
  2002年   100篇
  2001年   85篇
  2000年   83篇
  1999年   79篇
  1998年   78篇
  1997年   59篇
  1996年   42篇
  1995年   52篇
  1994年   64篇
  1993年   38篇
  1992年   24篇
  1991年   18篇
  1990年   10篇
  1989年   7篇
  1988年   11篇
  1987年   7篇
  1986年   12篇
  1985年   8篇
  1984年   6篇
  1982年   7篇
  1981年   5篇
  1980年   7篇
  1979年   9篇
  1978年   6篇
  1974年   2篇
  1973年   5篇
  1969年   2篇
  1968年   2篇
排序方式: 共有3348条查询结果,搜索用时 234 毫秒
921.
程建美 《环境与发展》2020,(1):111-111,113
现阶段,随着我国城市化建设的不断推进,一些大型工程的施工以及工业的发展,都成为了对于水资源造成污染和破坏的主要因素,因此对于水资源的保护迫在眉睫。为了能够进一步保护水资源,通过高效液相色谱来开展水环境监测工作,能够更加全面和高效地监测水资源的污染情况,进而为之后的水环境治理工作提供有力支持。本文主要阐述了高效液相色谱的系统构成,并分析了该技术在水环境监测工作中的具体应用。  相似文献   
922.
针对工业园区污水排放监管问题,以北京某园区为例,提出了水污染源精细化管控方案。按照多级防控的思路,在企业级、管网级、园区级建成在线监测系统和精细化管控平台,实现园区水环境监管的全覆盖,有效监控企业排污动态,实时掌握园区污水排放状况,为企业、园区管理部门和环保管理部门提供决策支持。  相似文献   
923.
水样经硝酸和过氧化氢消解,Tl~+被氧化为Tl~(3+),在王水和Fe~(3+)介质中,TlCl~-_4被聚氨酯泡塑吸附富集,沸水脱附后用石墨炉原子吸收光谱法测定。用硝酸钯-抗坏血酸基体改进剂提高测定灵敏度,方法在0μg/L~25.0μg/L范围内线性良好,方法检出限为0.01μg/L。实际样品加标后6次测定结果的RSD为3.0%~11.0%,平均加标回收率为95.0%~99.8%。有证标准物质的测定结果在标准值范围内,相对误差为-4.8%。  相似文献   
924.
Water security: Old concepts,new package,what value?   总被引:1,自引:0,他引:1  
Water security” has come to infiltrate prominent discourse in the international water and development community, and achieving it is often viewed as a new water sector target. Despite the elevated status that the concept has increasingly acquired, understandings of the term are murky and quantification is rare. To promote a more tangible understanding of the concept, this paper develops an index for evaluating water security at a country level. The index is comprised of indicators in five components considered to be critical to the concept: (i) basic needs; (ii) agricultural production; (iii) the environment; (iv) risk management; and (v) independence. Achieving water security in these components can be considered necessary but insufficient criteria to measure the achievement of security in related areas such as health, livelihoods, and industry. After populating indicators with data from Asia‐Pacific countries, results are interpreted and the viability of methods is discussed. This effort comprises an important first step for quantifying and assessing water security across countries, which should spur more concrete understanding of the term and discussion of its added value.  相似文献   
925.
To measure the long term retention and seasonal dynamics of an initial 4 kg addition of 133Cs into an 11.4-ha, 157,000 m3 reservoir (Pond 4, near Aiken, South Carolina, USA), the concentrations and inventories of 133Cs in the water column were measured at periodical intervals for 522 days following the 1 August, 1999 release. After rapid declines in concentrations and inventories during the first 90 days, the 133Cs concentrations in the water column declined at an average proportional rate of 0.004 d−1. However, there were periods of less rapid and more rapid rates of declines, and these were correlated with periods of increasing and decreasing K concentrations in the water column. The decline rates were less and the K concentrations greater in the winter than in the summer. In the deeper, neighboring monomictic reservoirs of Par Pond and Pond B, a yearly cycle of increasing and decreasing 137Cs concentrations in the water column is driven by anoxic remobilization of Cs from the sediments into a persistent summer hypolimnion. In Pond 4, whose mean depth of 1.6 m is too shallow to support a persistent anoxic hypolimnion, the pattern of yearly dynamics for K and Cs appear to be related to the accumulation and release of these elements from the extensive, seasonal macrophyte communities. The contrasting results between Pond 4 and Pond B suggest that a full appreciation of the relative importance of 1) anoxic remobilization and 2) accumulation and release by macrophytes in these systems remains to be established.  相似文献   
926.
Evans et al. (Journal of Agricultural and Environmental Ethics, 2008) have attempted to enmesh me in their dispute with the Florida Bureau of Invasive Plant Management about a specific system, Kings Bay/Crystal River. In so doing, they repeatedly mischaracterize my positions in order to depict, incorrectly, invasion biology as monolithic and me as a representative of one extreme of a false dichotomy about management of introduced species. In addition, they introduce an issue irrelevant in this case (extinctions) and cite incorrect data. Proposing to manage people, manatees, introduced plants, and cyanobacteria in Kings Bay by participative adaptive management, they ignore the fact that living organisms can both disperse autonomously and hitchhike. Finally, they present few details on any aspect of their management proposal and do not address the myriad problems that have beset previous attempts at scientific adaptive management, especially at large scales. Until such a management approach is fleshed out and implemented, it is impossible to assess its validity for Kings Bay, and it is very premature to suggest it as a general model for dealing with invasive species disputes.  相似文献   
927.
Abstract: Impact of watershed subdivision and soil data resolution on Soil Water Assessment Tool (SWAT) model calibration and parameter uncertainty is investigated by creating 24 different watershed model configurations for two study areas in northern Indiana. SWAT autocalibration tool is used to calibrate 14 parameters for simulating seven years of daily streamflow records. Calibrated parameter sets are found to be different for all 24 watershed configurations, however in terms of calibrated model output, their effect is minimal. In some cases, autocalibration is followed by manual calibration to correct for low flows, which were underestimated during autocalibration. In addition to normal validation using four years of streamflow data for each calibrated parameter set, cross‐validation (using a calibrated parameter set from one model configuration to validate observations using another configuration) is performed to investigate the effect of different model configurations on streamflow prediction. Results show that streamflow output during cross‐validation is not affected, thus highlighting the non‐unique nature of calibrated parameters in hydrologic modeling. Finally, parameter uncertainty is investigated by extracting good parameter sets during the autocalibration process. Parameter uncertainty analysis suggests that significant parameters show very narrow range of uncertainty across different watershed configurations compared with nonsignificant parameters. Results from recalibration of some configurations using only six significant parameters were comparable to that from calibration using 14 parameters, suggesting that including fewer significant parameters could reduce the uncertainty arising from model parameters, and also expedite the calibration process.  相似文献   
928.
Our recent paper advocating adaptive management of invasive nonnative species (INS) in Kings Bay, Florida received detailed responses from both Daniel Simberloff, a prominent invasion biologist, and Mark Sagoff, a prominent critic of invasion biology. Simberloff offers several significant lines of criticism that compel detailed rebuttals, and, as such, most of this reply is dedicated to this purpose. Ultimately, we find it quite significant that Simberloff, despite his other stated objections to our paper, apparently agrees with our argument that proposals for alternative management of established INS (i.e., alternatives to minimization/eradication) should not be rejected on an a␣priori basis. We argue that more specific development and application of adaptive approaches toward INS management, whether in Kings Bay or other appropriate case studies, would be facilitated if ecosystem managers and invasion biologists follow Simberloff’s lead on this key point. While Sagoff largely shares (and, indeed, served as a primary source for developing) our general arguments that challenge common moral and scientific assumptions associated with invasion biology, he does question our suggestion that participatory adaptive management provides an appropriate framework for approaching environmental problems in which science and politics are inherently entangled. We attempt to answer this criticism through a brief sketch of what participatory adaptive management might look like for Kings Bay and how such an approach would differ from past management approaches.  相似文献   
929.
Fragrance materials are widely present in the environment, such as air, water, and soil. Concerns have been raised due to the increasing utilization and suspected impact on human health. The bioaccumulating property is considered as one of the causes of the toxicity to human beings. The removal of fragrance materials from environmental sinks has not been paid enough attention due to the lack of regulation and research on their toxicity. This paper provides systematic information on how fragrance materials are transferred to the environment, how do they affect human lives, and what is their fate in water, wastewater, wastewater sludge, and soil.  相似文献   
930.
The fertilized eggs of Japanese medaka (Oryzias latipes) were exposed to estrone (E1) at 5–5000 ng L−1 for 15 d, and the hatched fry were exposed continuously to the same concentrations for the additional 15 d. Adverse effects on hatchability, time to hatching, and gross abnormalities occurred at 50 ng L−1 or above. Then the fry were divided into a continual exposure group, and a water recovery group. When the fry were exposed to E1 for another 60 d, there was a decrease in the hepatosomatic index (HSI) of males and the influence disappeared in the water recovery group. The gonadosonatic index (GSI) of females at 500 ng L−1 decreased significantly in another 60 d exposure. While the fry were maintained in dechlorinated tap water for 60 d, a significant decrease in female GSI was observed at 50 ng L−1 or above. An increased GSI was found in males in both continual exposure and water recovery groups at all E1 treatments. Quantitative RT-PCR showed that vitellogenin-I (Vtg-I) gene expressions in the female liver were significantly down-regulated at 50 ng L−1 in the continual exposure group, and at 500 ng L−1 in the water recovery group, while male Vtg-I genes were significantly up-regulated for all E1 treatments. In addition, all E1 treatments caused sex reversal of males. These results suggest that E1 at 5 ng L−1 or above have unrecoverable impacts on the gonadal growth and development of medaka, even if only early life stages were exposed to E1.  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