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   1794篇
  免费   56篇
  国内免费   21篇
安全科学   88篇
废物处理   70篇
环保管理   406篇
综合类   179篇
基础理论   506篇
环境理论   5篇
污染及防治   417篇
评价与监测   122篇
社会与环境   53篇
灾害及防治   25篇
  2023年   18篇
  2022年   36篇
  2021年   48篇
  2020年   24篇
  2019年   42篇
  2018年   53篇
  2017年   59篇
  2016年   78篇
  2015年   49篇
  2014年   66篇
  2013年   151篇
  2012年   84篇
  2011年   127篇
  2010年   79篇
  2009年   94篇
  2008年   105篇
  2007年   97篇
  2006年   104篇
  2005年   54篇
  2004年   50篇
  2003年   59篇
  2002年   45篇
  2001年   26篇
  2000年   44篇
  1999年   20篇
  1998年   19篇
  1997年   9篇
  1996年   21篇
  1995年   18篇
  1994年   20篇
  1993年   10篇
  1992年   11篇
  1991年   9篇
  1990年   8篇
  1989年   12篇
  1988年   11篇
  1987年   10篇
  1986年   11篇
  1985年   9篇
  1984年   5篇
  1983年   10篇
  1982年   13篇
  1981年   14篇
  1980年   4篇
  1979年   5篇
  1978年   6篇
  1977年   4篇
  1975年   4篇
  1969年   4篇
  1958年   2篇
排序方式: 共有1871条查询结果,搜索用时 171 毫秒
851.
Environmental Science and Pollution Research - In many countries, water supplies are limited and must be managed for different uses. Providing additional resources for irrigation can be an...  相似文献   
852.
Environmental Science and Pollution Research - The evidence base in environmental sciences is increasing steadily. Environmental researchers have been challenged to handle massive volumes of data...  相似文献   
853.
There is increasing recognition that diverse knowledge systems can work in mutually enriching ways and that Indigenous and Local Knowledge (ILK) can enhance biodiversity conservation. However, studies using scientific knowledge and ILK in a complementary manner, and acknowledging convergent and especially divergent insights have remained limited. In this study, we contrasted proxies of abundances and trends of threatened and conflict-prone carnivores (caracal, cheetah, jackal, lion, leopard, spotted hyaena, striped hyaena) derived separately from scientific knowledge and ILK. We conducted camera trapping, track surveys and semi-structured interviews with local pastoralists from northern Kenya. We found convergences highlighting the need for conservation action and divergences suggesting scientific ecological sampling limitations or underlying socio-psychological phenomena. Overall, our study shows that complementing scientific knowledge and ILK as separate sources of information and opening up space for discrepancies can enrich our understanding of the status and trends of carnivores, as well as recognizing human-carnivore relationships.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01443-4) contains supplementary material, which is available to authorized users.  相似文献   
854.
855.
856.
857.
Two distinctive, independently developed technologies, geographic information systems (GIS) and predictive water resource models, are being interfaced with varying degrees of sophistication in efforts to simultaneously examine spatial and temporal phenomena. Neither technology was initially developed to interact with the other, and as a result, multiple approaches to interface GIS with water resource models exist. Additionally, continued model enhancements and the development of graphical user interfaces (GUIs) have encouraged the development of application “suites” for evaluation and visualization of engineering problems. Currently, disparities in spatial scales, data accessibility, modeling software preferences, and computer resources availability prevent application of a universal interfacing approach. This paper provides a state‐of‐the‐art critical review of current trends in interfacing GIS with predictive water resource models. Emphasis is placed on discussing limitations to efficient interfacing and potential future directions, including recommendations for overcoming many current challenges.  相似文献   
858.
ABSTRACT: The distribution of sediment physical characteristics, sediment phosphorus (P) pools, and laboratory‐based rates of P release from the sediments were used to identify regions and dosage for alum treatment in Wind Lake, Wisconsin. Using variations in sediment moisture content, we identified an erosional zone at depths < 1.4 m and an accumulation zone at depths > 2.6 m. Mean concentrations of porewater P, loosely‐bound P, iron‐ and aluminum‐bound P, and mean rates of P release from sediments under anoxic conditions were high in the accumulation zone compared to sediment P characteristics in the erosional zone, indicating focusing of readily mobilized sediment P pools from shallow regions and accumulation to deep regions. We determined that a future alum treatment for control of internal P loading would be most effective at depths > 2.6 in the accumulation zone. The mean rate of anoxic P release from sediments encountered in the accumulation zone (8.3 mg m‐2 d‐1) was used in conjunction with a summer anoxic period of 122 d, and a treatment area of 1.6 km2 to estimate an internal P load of 1,600 kg to be controlled. Our results suggest that an understanding of the distribution of sediment P pools and P fluxes in lakes provides a strategy for estimating alum dosage and application areas.  相似文献   
859.
The literature critical of the Coase Theorem is synthesized. One conclusion is that bilateral bargaining in a voluntary, frictionless setting results in optimality only by accident, if at all. This is because of the problem of threats and the problem of small numbers bargaining behavior (it is not marginal). The second conclusion is that the placement of liability in general affects the allocation of resources. The exception is when there are no income effects, no transactions costs, and no nonseparabilities. But the existence of externalities implies transaction costs are high, which in turn implies that liability matters.  相似文献   
860.
Field studies showed that male Rhagoletis juglandis and R. boycei flies guard egg-laying punctures (and the eggs within) on host walnut (Juglans major) fruit and defend those sites from conspecific and heterospecific males. In field experiments with artificially punctured fruit,as well as field observations on unmanipulated fruit, males were consistently more likely to be sighted and stayed longer on damaged fruit than on undamaged fruit. On artificially punctured fruit, they consistently spent more time in the vicinity of a puncture than expected by chance alone. Males together on damaged fruit were more likely to engage in contests over those fruit than males together on undamaged fruit. Copulations were consistently more frequent for either species on damaged than undamaged fruit, both in observations of unmanipulated fruit and in artificial puncture experiments. Analyses which controlled for the longer male residence time on damaged fruit suggested strongly that copulations were consistently achieved at higher per capita rates on damaged than on undamaged fruit, indicating that puncture-guarding functions to increase access to females. An exception to the pattern in male mating success was noted at a site where both species used host fruit on the same trees. In this case, R. juglandis males were only slightly more common on punctured fruit than on control fruit and male success in copulation did not differ significantly between the two types of fruit. This anomalous result was apparently due to an almost absolute advantage enjoyed by R. boycei males in on-fruit contests with R. juglandis males. A likely basis for improvements in mating success associated with puncture guarding was a propensity for females to deposit eggs into existing punctures. Both in observations of unmanipulated fruit and in artificial puncture experiments, females consistently attempted oviposition more often in damaged than undamaged fruit. In artificial puncture experiments, both species at both sites deposited most clutches in damaged fruit. Mating generally took place as females initiated oviposition. The possible functions of puncture use by females as well as alternative functions of puncture guarding by males are discussed.  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