全文获取类型
收费全文 | 1143篇 |
免费 | 8篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 18篇 |
废物处理 | 45篇 |
环保管理 | 70篇 |
综合类 | 666篇 |
基础理论 | 138篇 |
污染及防治 | 167篇 |
评价与监测 | 32篇 |
社会与环境 | 18篇 |
灾害及防治 | 2篇 |
出版年
2017年 | 14篇 |
2015年 | 10篇 |
2014年 | 10篇 |
2013年 | 39篇 |
2012年 | 33篇 |
2011年 | 30篇 |
2010年 | 22篇 |
2009年 | 28篇 |
2008年 | 23篇 |
2007年 | 26篇 |
2006年 | 29篇 |
2005年 | 32篇 |
2004年 | 37篇 |
2003年 | 33篇 |
2002年 | 26篇 |
2001年 | 13篇 |
2000年 | 9篇 |
1998年 | 11篇 |
1995年 | 14篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1989年 | 9篇 |
1978年 | 10篇 |
1966年 | 10篇 |
1965年 | 15篇 |
1964年 | 15篇 |
1963年 | 25篇 |
1962年 | 17篇 |
1961年 | 14篇 |
1960年 | 23篇 |
1959年 | 24篇 |
1958年 | 15篇 |
1957年 | 16篇 |
1956年 | 15篇 |
1955年 | 27篇 |
1954年 | 33篇 |
1953年 | 19篇 |
1952年 | 14篇 |
1951年 | 24篇 |
1948年 | 9篇 |
1947年 | 11篇 |
1941年 | 9篇 |
1939年 | 9篇 |
1938年 | 12篇 |
1935年 | 8篇 |
1933年 | 9篇 |
1931年 | 11篇 |
1930年 | 12篇 |
1929年 | 13篇 |
1921年 | 8篇 |
排序方式: 共有1156条查询结果,搜索用时 0 毫秒
471.
Asbjørn Aaheim Hans A. Kristin Seip Hans M. 《Mitigation and Adaptation Strategies for Global Change》1999,4(1):61-81
Few studies on measures for mitigation of damage caused by man-made emissions to the environment have tried to consider all major effects. We illustrate the importance of an integrated approach by estimating costs and benefits of a proposed energy saving program for Hungary, originally designed to reduce CO2 emissions. The dominant benefit of implementing the program is likely to be reduced health damage from local pollutants. Also reduced costs of material damage and to a lesser extent vegetation damage contribute to make the net benefit considerable. Compared to the reduction in these local and regional effects, the benefits from reducing greenhouse gases are likely to be minor. Since local effects in general occur much earlier after measures have been implemented than effects of increased emissions of greenhouse gases, inclusion of local effects makes evaluation of climate policy less dependent on the choice of discount rate. In our opinion, similar results are likely for many measures originally designed to reduce emissions of greenhouse gases particularly in some areas in developing countries with high local pollution levels. Main uncertainties in the analysis, e.g. in the relationships between damage and pollution level, are discussed. 相似文献
472.
Hussain A Larsson H Kuktaite R Johansson E 《Journal of environmental science and health. Part. B》2012,47(7):751-758
The concentration of six HMs (Cd, Cr, Co, Pb, Hg and Ni) was analysed in 321 organically grown winter and spring wheat genotypes from six genotype groups, i.e. selections, old landraces, primitive wheat, spelt, old cultivars and cultivars. Also the potential risk of individual toxic HM to human health was estimated by using the Hazard Quotient (HQ). Significantly the lowest grain concentration of Cd was found in primitive wheat as compared to all other investigated genotype groups. Intake of HM by consumption of whole wheat grain was not found to pose a health risk to human for any of the investigated genotype groups. The bio-concentration factor of Cd for the different genotype groups indicated a lower ability to accumulate Cd for primitive wheat as compared to other genotype groups. The primitive wheat was found the most promising and might be of interest in future wheat breeding programs to develop wheat genotypes with low HMs concentration in the grain. 相似文献
473.
Britta Grote Wilhelm Hagen Marek R. Lipinski Hans M. Verheye Erling K. Stenevik Werner Ekau 《Marine Biology》2011,158(5):1005-1017
Cape hakes, Merluccius paradoxus and M. capensis, are important gadoid fish that are commercially harvested in the Benguela Current system off Namibia and South Africa. The
aim of this study was to elucidate the nutritional condition and feeding preferences of their larvae. Hake eggs and larvae
were sampled in austral spring of two consecutive years, 2007 and 2008, off the west coast of South Africa. They were identified
to species using genetics, and total lipid content and fatty acid (FA) composition were analysed for each individual egg and
larva to compare the condition of different early life stages of both hake species. Higher abundances of M. paradoxus eggs and larvae were consistently found compared to M. capensis. In both species, eggs contained wax esters (WE) and had significantly higher lipid content per dry mass than larvae. Lipid
content as well as FA composition changed with the developmental stage of larvae. Quantities of essential fatty acid (EFA)
increased with feeding of larvae due to dietary lipid incorporation. In 2007, yolk-sac larvae contained significantly lower
total lipids than in 2008. It is argued that this was due to reduced lipid transfer by the spawning females to the eggs. These
findings indicate that maternal effects are important in determining condition of hake larvae and that this may have an effect
on their survival and subsequent recruitment. 相似文献
474.
Ramona Maggini Anthony LehmannMarc Kéry Hans SchmidMartin Beniston Lukas JenniNiklaus Zbinden 《Ecological modelling》2011,222(1):21-32
Climate change is affecting biodiversity worldwide inducing species to either “move, adapt or die”. In this paper we propose a conceptual framework for analysing range shifts, namely a catalogue of the possible patterns of change in the distribution of a species along elevational or other environmental gradients and an improved quantitative methodology to identify and objectively describe these patterns. Patterns are defined in terms of changes occurring at the leading, trailing or both edges of the distribution: (a) leading edge expansion, (b) trailing edge retraction, (c) range expansion, (d) optimum shift, (e) expansion, (f) retraction, and (g) shift. The methodology is based on the modelling of species distributions along a gradient using generalized additive models (GAMs). Separate models are calibrated for two distinct periods of assessment and response curves are compared over five reference points. Changes occurred at these points are formalized into a code that ultimately designates the corresponding change pattern. We tested the proposed methodology using data from the Swiss national common breeding bird survey. The elevational distributions of 95 bird species were modelled for the periods 1999-2002 and 2004-2007 and significant upward shifts (all patterns confounded) were identified for 35% of the species. Over the same period, an increase in mean temperature was registered for Switzerland. In consideration of the short period covered by the case study, assessed change patterns are considered to correspond to intermediate patterns in an ongoing shifting process. However, similar patterns can be determined by habitat barriers, land use/land cover changes, competition with concurrent or invasive species or different warming rates at different elevations. 相似文献
475.
Testing sustainability by prospective and retrospective demographic analyses: evaluation for palm leaf harvest. 总被引:1,自引:0,他引:1
Harvesting nontimber forest products (NTFPs) is a major economic activity in tropical forests. As many NTFPs are overexploited, sustainability analyses are required to set harvest guidelines. Here we introduce and apply a new approach to evaluating sustainability, which combines prospective (elasticity) and retrospective (Life Table Response Experiments [LTRE]) demographic analyses of matrix population models. We relate the elasticity of vital rates (representing their importance for population growth rate, lamda) to their contribution to harvest-induced change in lamda ("LTRE contribution"). When high-elasticity vital rates have a low LTRE contribution, exploitation is potentially sustainable as negative effects for population growth are buffered. If the reverse is found, there is little scope for sustainability because crucial vital rates are affected. Our approach is less sensitive to chance fluctuations than the commonly used sustainability criterion of lamda = 1.0, as it does not depend on the absolute value of lamda. We applied this analysis to Geonoma deversa, a clustered forest understory palm. We studied three experimentally defoliated and control populations in a Bolivian rainforest during two years. Cutting all leaves of large ramets did not change mortality but strongly affected growth and reproduction. In spite of severe changes in some vital rates, population growth rate was not significantly reduced after defoliation. A literature review revealed that six other understory palms species responded very similarly to defoliation. The combination of LTRE contributions and elasticity analyses showed that low-elasticity vital rates were mainly responsible for the defoliation-induced change in lamda for Geonoma deversa. For two other understory palms (Astrocaryum mexicanum and Chamaedorea radicalis) new demographic analyses yielded very similar results. For Geonoma, the LTRE contribution-elasticity relation strongly changed when we mimicked harvest damage. Adding 5% mortality to defoliated palms caused stronger change in lamda, mainly due to changes in a high-elasticity vital rate (survival). Therefore, harvest practices that involve stem killing are clearly unsustainable. Our results show that commercial leaf cutting in Geonoma deversa is potentially sustainable, and that this is likely the case for understory palms in general. Our approach to evaluating harvest sustainability can be applied to other NTFPs. 相似文献
476.
Hans Toni Ratte 《Environmental Sciences Europe》2007,19(1):30-34
The paper presents a critical survey as to which extent various concept formations and applications from the ecotoxicological area deserve the attribute ‘scientific’. Among these are down-played names for biotests and often nearly constrainedly applied slogans like ‘from molecule to ecosystem’. These kind of phrases are called ‘ecospeak’. The author discusses as to how, e.g., the aforementioned slogan can give rise to scientific illfounded suggestions that molecular mechanisms can directly be extrapolated to the level of individuals and populations. He scrutinizes the belief in the ability to predict the behavior of communities and the biodiversity of habitats in the open landscape by using mechanistic concepts and models. The non-critical use of species-sensitivity distributions and the NOEC-determination using results from mesocosm experiments are also seen as a problem. The author criticizes the lack of environmental standards for the open landscape and advocates for a strong enhancement of research policy and funding. The deliberately subjective perceptions intend to initiate a discussion, as broad as possible, on the status quo in Ecotoxicology. 相似文献
477.
Glas B Stenberg B Stenlund H Sunesson AL 《Journal of environmental monitoring : JEM》2008,10(11):1297-1303
This article addresses problems that complicate attempts to compare methods when several factors may be associated with an effect, but it is not known which factors are relevant. Chemicals that may contribute to 'sick building syndrome' (SBS), and thus should be sampled in investigations of SBS, are not currently known. A study was undertaken to compare the utility of three adsorbents (Carbopack B, Chromosorb 106 and Tenax TA) for detecting differences in personal chemical exposure to volatile organic compounds in indoor air, between persons with and without SBS symptoms (cases and controls). On the basis of office workers' responses to a questionnaire, 15 cases and 15 controls were chosen. They simultaneously carried diffusive samplers with adsorbents during a week at work, and the acquired samples were analysed by gas chromatography/mass spectrometry (GC/MS). The adsorbents were then compared in terms of their ability to separate cases and controls in partial least square discriminant analysis (PLS-DA) models. This method of comparison takes into account detected differences in chemical exposure between cases and controls measured with the different adsorbents. Tenax TA gave the best PLS-DA models for separating cases and controls, but a combination of measurements with Tenax TA and Carbopack B gave better PLS-DA models than models based on measurements from either adsorbent alone. Adding measurements from Chromosorb 106 did not improve the results. 相似文献
478.
Evaluation of Progress in Achieving TMDL Mandated Nitrogen Reductions in the Neuse River Basin, North Carolina 总被引:2,自引:0,他引:2
Management efforts to control excess algal growth in the Neuse River and Estuary, North Carolina began in the 1980s, with
an initial focus on phosphorus (P) input reduction. However, continued water quality problems in the 1990s led to development
of a Total Maximum Daily Load (TMDL) for nitrogen (N) in 1999 to improve conditions in N-sensitive estuarine waters. Evaluation
of the effectiveness of management actions implemented in the Neuse River basin is a challenging endeavor due to natural variations
in N export associated with climate. A simplified approach is presented that allows evaluation of trends in flow-normalized
nutrient loading to provide feedback on effectiveness of implemented actions to reduce N loading to estuarine waters. The
approach is applied to five watershed locations, including the headwaters of the Neuse Estuary. Decreases in nitrate + nitrite
(NO3–N) concentrations occurred throughout the basin and were largest just downstream of the Raleigh metropolitan area. Conversely,
concentrations of total Kjeldahl N (TKN) increased at many stations, particularly under high flow conditions. This indicates
a relative increase in organic N (Org-N) inputs since the mid-1990s. Overall, patterns in different N fractions at watershed
stations indicate both partial success in reducing N inputs and ongoing challenges for N loading under high flow conditions.
In downstream waters, NO3–N concentrations decreased concurrent with TMDL implementation in the upper portion of the estuary but not in the middle
and lower reaches. The lack of progress in the middle and lower reaches of the estuary may, at least in part, be affected
by remineralization of settled particle-bound N deposited under high river flows. 相似文献
479.
Jozien T. J. Brons Hans J. Van Der Harten Herman P. Van Geijn Juri W. Wladimiroff Martinus F. Niermeuer Dick Lindhout Patricia A. Stuart Chris J. L. M. Meijer Nico F. Th Arts 《黑龙江环境通报》1990,10(5):279-288
Radial-ray reduction malformations (RRRMs) may occur isolated or in association with other anomalies. The data of seven fetuses born with RRRMs were collected. Six fetuses had associated lethal abnormalities of the central nervous system, urogenital system, and/or heart, detected by ultrasound. In five cases, it was possible to establish the precise diagnosis, enabling an informed prognosis and subsequent genetic counselling. The diagnoses were: Edwards syndrome (n=3), VACTERL association (n=1), and Poland-Moebius-like complex (n= 1). In two cases, a complete diagnosis was not possible because of inadequate evaluation of these fetuses before and/or after birth. A proposal is given for the diagnostic approach for infants with RRRMs detected in the antenatal period by means of ultrasonography. 相似文献
480.
Löfgren S Aastrup M Bringmark L Hultberg H Lewin-Pihlblad L Lundin L Karlsson GP Thunholm B 《Ambio》2011,40(8):836-856
Recovery from anthropogenic acidification in streams and lakes is well documented across the northern hemisphere. In this
study, we use 1996–2009 data from the four Swedish Integrated Monitoring catchments to evaluate how the declining sulfur deposition
has affected sulfate, pH, acid neutralizing capacity, ionic strength, aluminum, and dissolved organic carbon in soil water,
groundwater and runoff. Differences in recovery rates between catchments, between recharge and discharge areas and between
soil water and groundwater are assessed. At the IM sites, atmospheric deposition is the main human impact. The chemical trends
were weakly correlated to the sulfur deposition decline. Other factors, such as marine influence and catchment features, seem
to be as important. Except for pH and DOC, soil water and groundwater showed similar trends. Discharge areas acted as buffers,
dampening the trends in streamwater. Further monitoring and modeling of these hydraulically active sites should be encouraged. 相似文献