全文获取类型
收费全文 | 44385篇 |
免费 | 464篇 |
国内免费 | 441篇 |
专业分类
安全科学 | 1426篇 |
废物处理 | 2130篇 |
环保管理 | 5786篇 |
综合类 | 6517篇 |
基础理论 | 11566篇 |
环境理论 | 12篇 |
污染及防治 | 11360篇 |
评价与监测 | 3276篇 |
社会与环境 | 2933篇 |
灾害及防治 | 284篇 |
出版年
2023年 | 213篇 |
2022年 | 416篇 |
2021年 | 469篇 |
2020年 | 295篇 |
2019年 | 374篇 |
2018年 | 669篇 |
2017年 | 699篇 |
2016年 | 1102篇 |
2015年 | 791篇 |
2014年 | 1217篇 |
2013年 | 3718篇 |
2012年 | 1491篇 |
2011年 | 1955篇 |
2010年 | 1663篇 |
2009年 | 1705篇 |
2008年 | 2001篇 |
2007年 | 2038篇 |
2006年 | 1837篇 |
2005年 | 1582篇 |
2004年 | 1550篇 |
2003年 | 1487篇 |
2002年 | 1391篇 |
2001年 | 1735篇 |
2000年 | 1219篇 |
1999年 | 781篇 |
1998年 | 573篇 |
1997年 | 572篇 |
1996年 | 622篇 |
1995年 | 656篇 |
1994年 | 576篇 |
1993年 | 517篇 |
1992年 | 535篇 |
1991年 | 505篇 |
1990年 | 476篇 |
1989年 | 487篇 |
1988年 | 445篇 |
1987年 | 360篇 |
1986年 | 331篇 |
1985年 | 342篇 |
1984年 | 391篇 |
1983年 | 372篇 |
1982年 | 415篇 |
1981年 | 331篇 |
1980年 | 259篇 |
1979年 | 299篇 |
1978年 | 257篇 |
1977年 | 213篇 |
1976年 | 200篇 |
1975年 | 203篇 |
1973年 | 233篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
461.
Municipal solid waste generation in municipalities: quantifying impacts of household structure, commercial waste and domestic fuel 总被引:1,自引:0,他引:1
Waste management planning requires reliable data concerning waste generation, influencing factors on waste generation and forecasts of waste quantities based on facts. This paper aims at identifying and quantifying differences between different municipalities' municipal solid waste (MSW) collection quantities based on data from waste management and on socio-economic indicators. A large set of 116 indicators from 542 municipalities in the Province of Styria was investigated. The resulting regression model included municipal tax revenue per capita, household size and the percentage of buildings with solid fuel heating systems. The model explains 74.3% of the MSW variation and the model assumptions are met. Other factors such as tourism, home composting or age distribution of the population did not significantly improve the model. According to the model, 21% of MSW collected in Styria was commercial waste and 18% of the generated MSW was burned in domestic heating systems. While the percentage of commercial waste is consistent with literature data, practically no literature data are available for the quantity of MSW burned, which seems to be overestimated by the model. The resulting regression model was used as basis for a waste prognosis model (Beigl and Lebersorger, in preparation). 相似文献
462.
P. Valkering R. van der Brugge A. Offermans N. Rijkens-Klomp 《Regional Environmental Change》2011,11(2):229-241
Climate adaptation is a complex task surrounded by uncertainty. To support climate adaptation policies, a new scenario approach
is pursued to explore possible discontinuous future developments of societal perspectives on climate adaptation issues. The
scenario approach was tested for a case study on Dutch river management. In a series of scenario development workshops, a
select group of stakeholders explored the perspectives on the management of the River Meuse in the past, present, and future.
The process was supported by an analytical perspectives mapping tool to illustrate and analyze the development of perspectives
over time. The process and analytical tools contributed to insight into the drivers of perspective change for the case study
at hand. Moreover, the stakeholders highlighted the potential of the approach for water management policy for creating awareness
about the plurality of perspectives and the dynamics of perspective change, monitoring perspectives and perspective change
as part of a flexible policy approach, and anticipating on the occurrence of shock events. Further work is required to better
represent the social dynamics of perspectives change, to better empirically ground the perspective change model, and to apply
integrated water models in the scenario development process to assess water–society interactions. 相似文献
463.
A. M. Rusanov 《Russian Journal of Ecology》2011,42(1):30-37
Data are presented that show the significance of the humus state of chernozem soils, their amphiphilic (hydrophobic-hydrophilic) components, and related physical properties (density, structural condition, and water permeability) for regeneration of natural vegetation and restoration of its species com-position in pasture ecosystems. 相似文献
464.
465.
The results of studies on the radial increment of larch and pine in central Yakutia are presented. The application of dendroclimatological
methods to the study of tree-ring chronologies has made it possible to evaluate tree growth response to the dynamics of climatic
factors over the past 120 years. The results of analysis of radial tree increment show that the onset of the growing season
has shifted to earlier dates by the end of the 20th century. 相似文献
466.
Behavioral adaptations of ant species were studied in associations of different biotopes in the Crimean Mountains. The pattern
of an association was found to depend on the mode of the territorial behavior of dominant species, irrespective of their number.
The dominance hierarchy was more strict in monodominant than in bidominant associations. Ant species demonstrated different
behavioral strategies, plasticity of foraging, and avoidance of aggressive encounters. A method for formalizing interspecies
relationships and a model describing stochastic properties of the biological system are proposed, which can be useful in solving
various ethological and ecological problems. 相似文献
467.
N. Mithil Kumar K. Varaprasad G. Ramachandra Reddy G. Siva Mohan Reddy Y. Sivabharathi G. Venkata Subba Reddy S. Venkata Naidu 《Journal of Polymers and the Environment》2011,19(1):225-229
Synthesis and characterization of novel biodegradable, water soluble and optically active DL-malic acid (DMA) and citric acid
(CA) copolymers were studied for possible use as antibacterial agents. The copolymers were synthesized by direct bulk melt
condensation in the absence of a catalyst above 150 °C. Characterization of obtained copolymers was carried out with the help
of infrared absorption spectra, differential scanning calorimetry and thermo gravimetric analysis. The antibacterial activity
of copolymers against bacteria was investigated. The results obtained shows the above copolymers possess a broad wound dressing
activity against different types of bacteria and may be useful as antibacterial agents. 相似文献
468.
Scientific community and policy-makers share the common interest in identifying and evaluating potential impacts of climate change on ecosystems, relying mainly on probabilistic methods of exploring the risks. In this perspective, the concept of ensemble forecasting makes possible to handle uncertainties associated with climate risk analysis by focusing on a range of potential or probable impact scenarios rather than actualizing a single case. In this paper, an ensemble of simulations based on the Lund-Potsdam-Jena (LPJ) model was used to investigate the uncertainty upon predictions of the future Euro-Mediterranean vegetation distribution, carbon dynamics, and water budget. Twenty simulations from past to future were based on the combination of different climate inputs, vegetation model parameterizations, and configurations. The evaluation of results combined the separate deterministic future projections from the LPJ model into a single probabilistic projection, associating a likelihood degree in accordance with the most recent Intergovernmental Panel on Climate Change terminology. Results projected a general critical situation in terms of water availability, made more serious if considering that also the occurrence of extreme-related events, e.g., fires, is expected to become more frequent as favored by more recurrent drought episodes. Although more uncomfortable climate conditions were projected for vegetation, net primary production (NPP) was predicted to increase due to the potential enrichment of CO2 in atmosphere and its fertilization effects on vegetation. The combination of rising NPP and fire frequency may shape the carbon cycle components, as the carbon losses by fire also were projected to increase. 相似文献
469.
J. Lelieveld P. Hadjinicolaou E. Kostopoulou C. Giannakopoulos A. Pozzer M. Tanarhte E. Tyrlis 《Regional Environmental Change》2014,14(5):1937-1949
The eastern Mediterranean and Middle East, a region with diverse socioeconomic and cultural identities, is exposed to strong climatic gradients between its temperate north and arid south. Model projections of the twenty-first century indicate increasing hot weather extremes and decreasing rainfall. We present model results, which suggest that across the Balkan Peninsula and Turkey climate change is particularly rapid, and especially summer temperatures are expected to increase strongly. Temperature rise can be amplified by the depletion of soil moisture, which limits evaporative cooling, prompted by the waning of large-scale weather systems that generate rain. Very hot summers that occurred only rarely in the recent past are projected to become common by the middle and the end of the century. Throughout the region, the annual number of heat wave days may increase drastically. Furthermore, conditions in the region are conducive for photochemical air pollution. Our model projections suggest strongly increasing ozone formation, a confounding health risk factor particularly in urban areas. This adds to the high concentrations of aerosol particles from natural (desert dust) and anthropogenic sources. The heat extremes may have strong impacts, especially in the Middle East where environmental stresses are plentiful. 相似文献
470.
D. González-Zeas S. Quiroga A. Iglesias L. Garrote 《Regional Environmental Change》2014,14(5):1983-1993
The effects of climate change on agriculture are often characterised by changes in the average productivity of crops; however, these indicators provide limited information regarding the risks associated with fluctuations in productivity resulting from future changes in climate variability that may also affect agriculture. In this context, this study evaluates the combined effects of the risks associated with anomalies reflected by changes in the mean crop yield and the variability of productivity in European agro-climatic regions under future climate change scenarios. The objective of this study is to evaluate adaptation needs and to identify regional effects that should be addressed with greater urgency in the light of the risks and opportunities that are identified. The results show differential effects on regional agriculture and highlight the importance of considering both regional average impacts and the variability in crop productivity in setting priorities for the adaptation and maintenance of rural incomes and agricultural insurance programmes. 相似文献