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   4909篇
  免费   212篇
  国内免费   115篇
安全科学   246篇
废物处理   50篇
环保管理   1199篇
综合类   2126篇
基础理论   323篇
环境理论   19篇
污染及防治   340篇
评价与监测   690篇
社会与环境   202篇
灾害及防治   41篇
  2023年   29篇
  2022年   29篇
  2021年   54篇
  2020年   169篇
  2019年   62篇
  2018年   63篇
  2017年   125篇
  2016年   152篇
  2015年   118篇
  2014年   204篇
  2013年   257篇
  2012年   167篇
  2011年   348篇
  2010年   181篇
  2009年   313篇
  2008年   251篇
  2007年   250篇
  2006年   235篇
  2005年   137篇
  2004年   152篇
  2003年   210篇
  2002年   191篇
  2001年   188篇
  2000年   218篇
  1999年   195篇
  1998年   164篇
  1997年   168篇
  1996年   100篇
  1995年   76篇
  1994年   92篇
  1993年   90篇
  1992年   61篇
  1991年   34篇
  1990年   19篇
  1989年   21篇
  1988年   12篇
  1987年   10篇
  1986年   18篇
  1985年   15篇
  1984年   15篇
  1983年   5篇
  1982年   8篇
  1981年   7篇
  1980年   4篇
  1979年   1篇
  1978年   11篇
  1977年   6篇
  1974年   1篇
排序方式: 共有5236条查询结果,搜索用时 15 毫秒
1.
• A survey on individual’s perception of SARS-CoV-2 transmission was conducted. • Waterborne transmission risks are far less perceived by individuals. • Precautions of preventing wastewater mediated transmission are implemented. • The precautions for wastewater transmission are less favored by the public. • Education level differs the most regarding to waterborne transmission perception. SARS-CoV-2 has been detected in various environmental media. Community and individual-engaged precautions are recommended to stop or slow environmentally-mediated transmission. To better understand the individual’s awareness of and precaution to environmental dissemination of SARS-CoV-2, an online survey was conducted in Beijing during March 14–25, 2020. It is found that the waterborne (especially wastewater mediated) spreading routes are far less perceived by urban communities. The precautions for wastewater transmission are less favored by the public than airborne and solid waste mediated spreading routes. Such risk communication asymmetry in waterborne transmission will be further enlarged in places with fragile water system. Furthermore, education level is the most significant attribution (Sig.<0.05) that causes the difference of awareness and precautions of the waterborne transmission among the respondents, according to the variance analysis results. Our survey results emphasize the urgent need for evidence-based, multifactorial precautions for current and future outbreaks of COVID-19.  相似文献   
2.
Air pollution is one of the primary concerns of our society for its effect on human health and the environment. Among the policy measures that can be put in place to limit air pollutant emissions, end-of-pipe technologies and/or regulatory instruments may be implemented through legislative acts. Also, equally important are behavioural measures, requiring citizens’ active involvement. The success of any measure to limit pollutant emissions requires the acceptance by the citizens that, in turn, implies a correct perception of the main pollutant emission drivers. We present here the comparison between the public perception of air pollution sources and the real-world situation through a survey carried out in seven European countries and involving 16 101 respondents. Our study shows a dramatic underestimation of the contribution of the agri-food sector to air pollution. This result is common to all respondents in the seven countries examined and only to a small extent depends on gender, age and socio-economic status of the respondents.  相似文献   
3.
• Aerosol transmission is an indispensable route of COVID-19 spread. • Different outbreak sites have different epidemiologic feature. • SRAS-CoV-2 can exist for a long time in aerosol. • SRAS-CoV-2 RNA can be detected in aerosol in diverse places. • Some environmental factors can impact SARS-CoV-2 transportation in aerosol. Patients with COVID-19 have revealed a massive outbreak around the world, leading to widespread concerns in global scope. Figuring out the transmission route of COVID-19 is necessary to control further spread. We analyzed the data of 43 patients in Baodi Department Store (China) to supplement the transmission route and epidemiological characteristics of COVID-19 in a cluster outbreak. Incubation median was estimated to endure 5.95 days (2–13 days). Almost 76.3% of patients sought medical attention immediately upon illness onset. The median period of illness onset to hospitalization and confirmation were 3.96 days (0–14) and 5.58 days (1–21), respectively. Patients with different cluster case could demonstrate unique epidemiological characteristics due to the particularity of outbreak sites. SRAS-CoV-2 can be released into the surrounding air through patient’s respiratory tract activities, and can exist for a long time for long-distance transportation. SRAS-CoV-2 RNA can be detected in aerosol in different sites, including isolation ward, general ward, outdoor, toilet, hallway, and crowded public area. Environmental factors influencing were analyzed and indicated that the SARS-CoV-2 transportation in aerosol was dependent on temperature, air humidity, ventilation rate and inactivating chemicals (ozone) content. As for the infection route of case numbers 2 to 6, 10, 13, 16, 17, 18, 20 and 23, we believe that aerosol transmission played a significant role in analyzing their exposure history and environmental conditions in Baodi Department Store. Aerosol transmission could occur in some cluster cases when the environmental factors are suitable, and it is an indispensable route of COVID-19 spread.  相似文献   
4.
● B[a]P, nicotine and phenanthrene molecules altered the secondary structure of Aβ42. ● β-content of the peptide was significantly enhanced in the presence of the PAHs. ● Nicotine made stable cluster with Aβ42 peptide via hydrogen bonds. ● Phenanthrene due to its small size, interfered with the Aβ42 monomer more strongly. Recent studies have correlated the chronic impact of ambient environmental pollutants like polycyclic aromatic hydrocarbons (PAHs) with the progression of neurodegenerative disorders, either by using statistical data from various cities, or via tracking biomarkers during in-vivo experiments. Among different neurodegenerative disorders, PAHs are known to cause increased risk for Alzheimer’s disease, related to the development of amyloid beta (Aβ) peptide oligomers. However, the complex molecular interactions between peptide monomers and organic pollutants remains obscured. In this work, we performed an atomistic molecular dynamics study via GROMACS to investigate the structure of Aβ42 peptide monomer in the presence of benzo[a]pyrene, nicotine, and phenanthrene. Interestingly the results revealed strong hydrophobic, and hydrogen-bond based interactions between Aβ peptides and these environmental pollutants that resulted in the formation of stable intermolecular clusters. The strong interactions affected the secondary structure of the Aβ42 peptide in the presence of the organic pollutants, with almost 50 % decrease in the α-helix and 2 %–10 % increase in the β-sheets of the peptide. Overall, the undergoing changes in the secondary structure of the peptide monomer in the presence of the pollutants under the study indicates an enhanced formation of Aβ peptide oligomers, and consequent progression of Alzheimer’s disease.  相似文献   
5.
This study investigated the levels, sources and ecological risks of 16 polycyclic aromatic hydrocarbons (PAHs) in two sediment cores that were collected along the Huaxi Reservoir. The spatial distributions and residue levels of the 16 priority PAHs in the sediments from the Huaxi Reservoir were analyzed for their potential ecological risk, source apportionment and contribution to the total PAH residue. The concentration level of the total PAHs (TPAHs) was in the range 1805 ng·g?1 to 20023 ng·g?1 based on dry weight, and the content of PAHs in the Huaxi Reservoir exhibited a gradual upward trend. The PAH congener ratios fluoranthene/(fluoranthene + pyrene) and indeno[1, 2, 3-cd]pyrene/(indeno[1, 2, 3-cd]pyrene + benzo[g, h, i]perylene) were used to identify the source. The main source of the low molecular weight PAHs was wood and coal combustion, whereas the high molecular weight PAHs were primarily from petroleum combustion sources. The results of an ecological risk assessment demonstrated that ACE poses a potential ecological risk, while FLU, NAP, ANT, BaP, DBA, PHEN and PYR can have serious ecological risks.  相似文献   
6.
基于环境卫星CCD数据的黄海浒苔遥感监测   总被引:1,自引:1,他引:0  
2007年以来,黄海海域每年夏季都发生大面积浒苔绿藻潮,影响沿岸人民的生活、生产。考虑到其分布范围动则几千、上万平方公里,水面监测很难实施,尝试利用遥感技术对其分布和发展变化情况进行监测。基于中国自主产权的环境卫星(HJ1)数据,采用经典植被指数算法和人工辅助判读方法,对2013年黄海浒苔暴发全过程进行了连续遥感监测,分析了此次浒苔过程的分布和漂移路线。监测结果表明,浒苔绿藻潮首发于江苏盐城东部海域,由南向北逐渐漂移,面积逐渐扩大,结束于青岛东北部海域;该期间,浒苔最大覆盖面积达663.54平方公里。  相似文献   
7.
从证据法学概念的角度浅析了环境监测原始记录的证据范畴,根据其所属范畴的证据要求,归纳了环境监测原始记录的证据要求。结合实例,分析了环境监测原始记录存在的不足,并提出了改进建议。  相似文献   
8.
新的《火电厂大气污染物排放标准》和新《环境保护法》实施后,燃煤火电企业的依法治企自觉性不断提高,但由于不同的环保管理文件对超标处罚依据和处罚手段不同,造成政府对企业处罚的自由裁量权加大,对企业造成一定的压力与困惑。结合企业实际运行情况对燃煤电厂大气污染物排放考核时间间隔提出建议。  相似文献   
9.
The objective of this paper is to discuss the main barriers for modelling and integrating the environmental performances in the automotive concept design. Incorporating environmental assessment in the early design phase of a vehicle component is known as an important challenge that car makers need to face in order to develop more sustainable design solutions; in this regard, the Life Cycle Assessment is the most widespread methodology for the environmental assessment and comparison of alternatives. The present work illustrates the combination of such methodology with the traditional design procedure at two different levels of the component design phase, material choice and concept design. In particular, the potential benefits originated by a lightweight solution for the automotive component Throttle Body are evaluated by considering environmental and technical implications at the same level. The case study shows that a multi-disciplinary approach for design effectively allows the integration of the environmental issue in the company’s established procedures. However, interpretation of results is still a challenging aspect due to the inevitable contradicting elements which should not discourage to develop comprehensive sustainability assessment within the early design stage.  相似文献   
10.
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