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   1396篇
  免费   88篇
  国内免费   93篇
安全科学   305篇
废物处理   34篇
环保管理   184篇
综合类   687篇
基础理论   71篇
污染及防治   81篇
评价与监测   189篇
社会与环境   13篇
灾害及防治   13篇
  2024年   3篇
  2023年   9篇
  2022年   14篇
  2021年   29篇
  2020年   29篇
  2019年   24篇
  2018年   23篇
  2017年   39篇
  2016年   45篇
  2015年   45篇
  2014年   61篇
  2013年   87篇
  2012年   118篇
  2011年   105篇
  2010年   78篇
  2009年   82篇
  2008年   57篇
  2007年   92篇
  2006年   86篇
  2005年   95篇
  2004年   68篇
  2003年   73篇
  2002年   48篇
  2001年   43篇
  2000年   38篇
  1999年   40篇
  1998年   23篇
  1997年   25篇
  1996年   29篇
  1995年   20篇
  1994年   13篇
  1993年   9篇
  1992年   7篇
  1991年   7篇
  1990年   4篇
  1989年   2篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1978年   1篇
排序方式: 共有1577条查询结果,搜索用时 15 毫秒
991.
During the last decade, many studies have focused on the detrimental effects of noise pollution on acoustic communication. Surprisingly, although it is known that noise exposure strongly influences health in humans, studies on wildlife remain scarce. In order to gain insight into the consequences of traffic noise exposure, we experimentally manipulated traffic noise exposure as well as the endocrine status of animals to investigate physiological and phenotypic consequences of noise pollution in an anuran species. We showed that noise exposure increased stress hormone level and induced an immunosuppressive effect. In addition, both traffic noise exposure and stress hormone application negatively impacted H. arborea vocal sac coloration. Moreover, our results suggest profound changes in sexual selection processes because the best quality males with initial attractive vocal sac coloration were the most impacted by noise. Hence, our study suggests that the recent increases in anthropogenic noise worldwide might affect a broader range of animal species than previously thought, because of alteration of visual signals and immunity. Generalizing these results to other taxa is crucial for the conservation of biodiversity in an increasingly noisy world.  相似文献   
992.
Assessing anthropogenic effects on biological diversity, identifying drivers of human behavior, and motivating behavioral change are at the core of effective conservation. Yet knowledge of people's behaviors is often limited because the true extent of natural resource exploitation is difficult to ascertain, particularly if it is illegal. To obtain estimates of rule‐breaking behavior, a technique has been developed with which to ask sensitive questions. We used this technique, unmatched‐count technique (UCT), to provide estimates of bushmeat poaching, to determine motivation and seasonal and spatial distribution of poaching, and to characterize poaching households in the Serengeti. We also assessed the potential for survey biases on the basis of respondent perceptions of understanding, anonymity, and discomfort. Eighteen percent of households admitted to being involved in hunting. Illegal bushmeat hunting was more likely in households with seasonal or full‐time employment, lower household size, and longer household residence in the village. The majority of respondents found the UCT questions easy to understand and were comfortable answering them. Our results suggest poaching remains widespread in the Serengeti and current alternative sources of income may not be sufficiently attractive to compete with the opportunities provided by hunting. We demonstrate that the UCT is well suited to investigating noncompliance in conservation because it reduces evasive responses, resulting in more accurate estimates, and is technically simple to apply. We suggest that the UCT could be more widely used, with the trade‐off being the increased complexity of data analyses and requirement for large sample sizes. Una Aproximación Novedosa para Evaluar la Prevalencia y Factores de la Cacería Ilegal en el Serengueti  相似文献   
993.
Concentrations of the elements Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were measured in the leaves and bark of Robinia pseudoacacia and the soil in which it grew, in the town of Ole?nica (SW Poland) and at a control site. We selected this town because emission from motor vehicles is practically the only source of air pollution, and it seemed interesting to evaluate its influence on soil and plants. The self-organizing feature map (SOFM) yielded distinct groups of soils and R. pseudoacacia leaves and bark, depending on traffic intensity. Only the map classifying bark samples identified an additional group of highly polluted sites along the main highway from Wroc?aw to Warszawa. The bark of R. pseudoacacia seems to be a better bioindicator of long-term cumulative traffic pollution in the investigated area, while leaves are good indicators of short-term seasonal accumulation trends.  相似文献   
994.
综述了2008年我国噪声振动与控制行业的发展状况,分析了行业发展存在的主要问题,提出了对策建议,并对行业的发展进行了展望。  相似文献   
995.
An injected tracer field experiment was conducted at the University of Idaho Ground Water Field Laboratory to evaluate the application of borehole-to-surface voltage measurements for delineation of the tracer distribution in partially saturated, fractured basalt. A tap water tracer was injected into a fracture-dominated, salt-water plume formed during a previous salt-water injection experiment. The tap water tracer was injected into a central injection well under constant hydraulic head for 34 days. The injection well was surrounded by seven test boreholes. Each borehole contained several copper wire electrodes for borehole-to-surface potential measurements between a surface grid of 224 copper sulfate, porous pot electrodes. Eight pole-pole, borehole-to-surface voltage data sets were acquired during each measurement period by energization of a selected electrode in each of the eight boreholes. Predicted voltages for a uniform earth (homogeneous and isotropic) potential model (finite difference) were subtracted from each data set (for its respective current source location), and the voltage residuals superposed to create new data sets with greater measurement sensitivity and coverage, to aid in interpretation. These data sets were collected over four measurement periods during tap water injection and four measurement periods during the subsequent 64-day drainage phase. The data were interpreted with the use of three-dimensional models and by comparisons with other electrical and hydrological observations. Results indicate that superposition of multiple data sets of voltage residuals significantly improved the lateral resolution of subsurface bulk resistivity changes that occurred over time.  相似文献   
996.
The effect of vehicle fleet mass on car crash fatalities was estimated, using a new mathematical model to isolate vehicle mass from related factors like size, stiffness and inherent protection. The model was based on fatality risk data, impact speed, fleet mass distribution, and collision probabilities. The fleet mass distribution was changed over 15 years to (a) a homogeneous fleet of 1300 kg cars, (b) a bimodal fleet of 600 and 1600 kg cars, and (c) a 300 kg lighter fleet.

Occupant and collision partner fatality risks were estimated for the new fleets. The new fleets were achieved by various strategies, and the average fatality rate was calculated after and during the transition to the new fleet.Occupant fatality risk decreased and partner risk increased as occupants changed to a heavier car. The average fatality rate was 59% higher after the transition to a bimodal fleet mass, and 11 % lower for a homogeneous fleet. A 300 kg lighter fleet had a 8% higher fatality rale, but the strategy influenced the number of fatalities accumulated during the transition. The safest strategy to attain the lighter fleet was to reduce the mass of the heaviest cars first.

It was concluded that vehicle fleet mass significantly affects traffic safety. Downsizing consequences can be compensated for by improving inherent vehicle protection or reducing impact speed. The fatalities during downsizing can be limited by choosing an appropriate strategy.  相似文献   
997.
分析了济钢中板厂精整区噪声污染严重的原因。采取了吸音材抖、消声设备、加强个体防护等措施,使总声压级由105dB降到72dB,保护了职工的身体健康。  相似文献   
998.
随着社会经济的迅速发展.交通噪声污染对环境和人们健康的影响受到更多的关注。磨山风景区位于武汉市武昌东郊.该区域环境噪声应执行0类标准。本文系统监测了磨山风景区的交通噪声污染状况,借鉴了比例预测法对其未来五年的交通噪声发展趋势进行了预测,并提出了相应控制对策。  相似文献   
999.
为研究城市轨道交通高架和地下站台噪声的规律和特点,选取某条线路中的3个高架站台以及3条线路中的7个地下站台进行实地测量,并对测量结果进行分析。研究结果表明:地下站台LAeq值都低于标准限值80 dB(A);站台的中心测点列车进站LAeq值和列车出站LAeq值都非常接近,使用T检验结果得出各站台中心测点列车进站LAeq值和列车出站LAeq值不存在显著差异(P>0.05);站台测量时要考虑大客流带来的喧闹声;站台最大噪声值是列车出站时,位于站台列车车头停止位置。  相似文献   
1000.
为科学规划农村生活污水治理,进一步解决西南地区农村生活污水粗放、分散等问题.在充分调研沿滩区农村生活污水现状,收集国土、人口、DEM、水系、水源保护区等多项数据,建立了农村居民聚集区识别、环境敏感村划定方法,识别出沿滩区48个环境敏感区村庄、74个农村聚居区,构建出更为科学的农村生活污水治理规划体系,为农村生活污水整治...  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