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   489篇
  免费   10篇
  国内免费   3篇
安全科学   16篇
废物处理   19篇
环保管理   114篇
综合类   65篇
基础理论   114篇
环境理论   1篇
污染及防治   100篇
评价与监测   53篇
社会与环境   12篇
灾害及防治   8篇
  2023年   2篇
  2022年   3篇
  2021年   4篇
  2020年   4篇
  2019年   7篇
  2018年   10篇
  2017年   10篇
  2016年   10篇
  2015年   10篇
  2014年   19篇
  2013年   26篇
  2012年   19篇
  2011年   33篇
  2010年   19篇
  2009年   20篇
  2008年   18篇
  2007年   31篇
  2006年   28篇
  2005年   19篇
  2004年   23篇
  2003年   20篇
  2002年   13篇
  2001年   16篇
  2000年   14篇
  1999年   10篇
  1998年   4篇
  1997年   6篇
  1996年   10篇
  1995年   5篇
  1994年   10篇
  1993年   10篇
  1992年   6篇
  1991年   6篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   6篇
  1986年   9篇
  1985年   2篇
  1984年   5篇
  1983年   3篇
  1982年   1篇
  1981年   4篇
  1979年   2篇
  1978年   4篇
  1973年   1篇
  1972年   1篇
  1970年   3篇
  1967年   1篇
排序方式: 共有502条查询结果,搜索用时 15 毫秒
341.
342.
Davies‐Colley, Robert J., David G. Smith, Robert C. Ward, Graham G. Bryers, Graham B. McBride, John M. Quinn, and Mike R. Scarsbrook, 2011. Twenty Years of New Zealand’s National Rivers Water Quality Network: Benefits of Careful Design and Consistent Operation. Journal of the American Water Resources Association (JAWRA) 47(4):750‐771. DOI: 10.1111/j.1752‐1688.2011.00554.x Abstract: This paper reviews New Zealand’s National Rivers Water Quality Network (NRWQN), which is now in its third decade of monitoring. The NRWQN is noteworthy for being operationally stable throughout its history, and the resulting consistency is increasingly valuable for detecting water quality trends and for “anchoring” temporary special purpose monitoring campaigns. The NRWQN was carefully designed following considerable effort to learn from monitoring experiences elsewhere. Monthly visits are made to 77 sites (all near hydrometric stations) on 35 river systems that cumulatively drain about one half of the national landscape. “Core” (routinely measured) variables are: conductivity, pH, temperature, dissolved oxygen, visual clarity, turbidity, colored dissolved organic matter, fecal indicator bacteria, and different forms of nitrogen and phosphorus (italics indicate field measurements). Associated benthic biological monitoring comprises monthly visual assessment of periphyton and annual sampling for macro‐invertebrates. We overview the conception, design, initiation, and operational history of the NRWQN, and highlight the diverse applications of its datasets including numerous scientific applications, national‐scale modeling of material fluxes, and state‐of‐environment reporting and practical water management at both regional and national scale. The qualified success of the NRWQN can probably be attributed to careful (and parsimonious) design and consistent operation.  相似文献   
343.
344.
Dislocating identity: Desegregation and the transformation of place   总被引:2,自引:0,他引:2  
Whatever other changes it engenders, desegregation invariably produces a re-organization of space and place, a fact whose implications the psychological literature on the process has generally disregarded. The present article begins to address this gap. Drawing on research on place–identity processes, we argue that desegregation may alter not only the relationship between self and other, but also the relationship between self and place. As such, it may be experienced as a form of dislocation: an event that undermines shared constructions of place and the forms of located subjectivity they sustain. In order to develop this idea, we analyse a series of interviews conducted with holiday-makers on a formerly white but now multiracial beach in South Africa. The analysis demonstrates how white respondents’ stories of desegregation evince an abiding concern with the loss of place, manifest in terms of an erosion of a sense of place belonging, attachment and familiarity and an undermining of the beach's capacity to act as a restorative environment of the self. The implications of such accounts for understanding personal and ideological resistance to desegregation are explored. The paper concludes by arguing that this problem provides an opportunity to conjoin environmental and social psychological work.  相似文献   
345.
This paper is concerned with whether long-term unemployment (6-24 months) affects people's attitudes to employment once they have found a new job. One hundred and forty men aged 25-40 were asked whether they felt various aspects of employment (e.g. job security, pay) are more important to them as a result of being unemployed. The effects of mental well-being when unemployed on attitudes to employment are explored. Unemployment is reported to have made most aspects of employment more important to people. Those whose mental health was worst when unemployed report that job security is most important to them.  相似文献   
346.
Cores from four Scottish ombrotrophic peat bogs were used to reconstruct the historical record of atmospheric vanadium (V) deposition in Scotland over the last 150 years. The general similarity of V and Pb concentration profile trends in (210)Pb-dated cores from each of the sites strongly suggested that V, like Pb, is essentially immobile in ombrotrophic peat. After allowance via use of the conservative element Ti for the contribution of soil dust V, the deposition of anthropogenic V was found to be greatest (~ 1.3 to 2.0 mg m(-2) y(-1)) in the mid-20(th) century before decreasing to 0.1-0.3 mg m(-2) y(-1) in the early years of the 21(st) century. The latter values were in good agreement with directly measured atmospheric V fluxes at nearby sites, a finding also observed in the case of Pb. The decline in peat-core-derived fluxes for both V and Pb from 1970 to 2004, however, was not as large as the decline in official UK emission estimates for the two metals during this period. This, along with an order of magnitude discrepancy between the anthropogenic V/Pb ratios at the peat core surface and the higher values of the ratio for UK emissions in the early 2000s, suggests that the recently revised UK emissions data for V may perhaps still be overestimated and/or that some previously deposited Pb is being resuspended in the atmosphere.  相似文献   
347.
348.
Male Chinese hamsters were exposed to diesel exhaust and clean air for six months at the Center Hill Facility of the U.S. Environmental Protection Agency in Cincinnati, Ohio. The animals were kept in specially constructed inhalation chambers and exposed to clean air or diesel exhaust for eight hours daily. The animals were sacrificed and slides prepared to study the mutagenic effects of diesel exhaust by four in vivo short term mammalian bioassays. Sperm morphology bioassay revealed a 2.67-fold increase in sperm abnormalities in the animals exposed to diesel exhaust as compared to those exposed to fresh air. Micronucleus bioassay revealed a 50% increase in the number of micronuclei in polychromatic erythrocytes obtained from animals exposed to diesel exhuast. However, no increase in sister chromatid exchange or chromosomal abnormalities was observed in bone marrow cells of animals treated with diesel exhaust. During these studies a decrease in mitotic index was observed in animals treated with diesel exhaust.  相似文献   
349.
To examine the preferences of experts to selected economic and policy options in ground-water protection, we conducted an exploratory survey. We presented a group of 120 experts with an analysis of the problem of radium in drinking water supplies of Iowa, and requested their response to a variety of formal questions pertaining to specific issues related to the presence of radium in drinking water. Ninety-seven of the 120 responded. We observed definite preferences in responses to certain aspects of the problem, although in some cases their responses differed significantly due to such factors as length of ground-water related professional experience and residential status. When the presence of excessive radium in drinking water is identified, the respondents preferred immediate action in a world of incomplete knowledge over extensive future research; were willing to undertake personal action to seek radium-free water rather than wait for official action; and favoured local and state government involvement over federal intervention. Findings based on such exploratory surveys can be of much value in defining insightful research hypotheses for field testing. Confirmatory testing of such hypotheses to establish actual preferences in communities with excessive radium in drinking water is a valuable area for further research.  相似文献   
350.
An extreme example of a low light-level lifestyle among flying birds is provided by the oilbird, Steatornis caripensis (Steatornithidae, Caprimulgiformes). Oilbirds breed and roost in caves, often at sufficient depth that no daylight can penetrate, and forage for fruits at night. Using standard microscopy techniques we investigated the retinal structure of oilbird eyes and used an ophthalmoscopic reflex technique to determine the parameters of these birds visual fields. The retina is dominated by small rod receptors (diameter 1.3±0.2 m; length 18.6±0.6 m) arranged in a banked structure that is unique among terrestrial vertebrates. This arrangement achieves a photoreceptor density that is the highest so far recorded (1,000,000 rods mm–2) in any vertebrate eye. Cone photoreceptors are, however, present in low numbers. The eye is relatively small (axial length 16.1±0.2 mm) with a maximum pupil diameter of 9.0±0.0 mm, achieving a light-gathering capacity that is the highest recorded in a bird (f-number 1.07). The binocular field has a maximum width of 38° and extends vertically through 100° with the bill projecting towards the lower periphery; a topography that suggests that vision is not used to control bill position. We propose that oilbird eyes are at one end of the continuum that juxtaposes the conflicting fundamental visual capacities of sensitivity and resolution. Thus, while oilbird visual sensitivity may be close to a maximum, visual resolution must be low. This explains why these birds employ other sensory cues, including olfaction and echolocation, in the control of their behaviour in low-light-level environments.  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