全文获取类型
收费全文 | 17517篇 |
免费 | 143篇 |
国内免费 | 114篇 |
专业分类
安全科学 | 407篇 |
废物处理 | 659篇 |
环保管理 | 1912篇 |
综合类 | 5484篇 |
基础理论 | 3595篇 |
环境理论 | 2篇 |
污染及防治 | 4139篇 |
评价与监测 | 898篇 |
社会与环境 | 617篇 |
灾害及防治 | 61篇 |
出版年
2018年 | 201篇 |
2017年 | 192篇 |
2016年 | 289篇 |
2015年 | 218篇 |
2014年 | 323篇 |
2013年 | 1164篇 |
2012年 | 375篇 |
2011年 | 521篇 |
2010年 | 499篇 |
2009年 | 555篇 |
2008年 | 585篇 |
2007年 | 606篇 |
2006年 | 531篇 |
2005年 | 467篇 |
2004年 | 511篇 |
2003年 | 466篇 |
2002年 | 440篇 |
2001年 | 618篇 |
2000年 | 413篇 |
1999年 | 284篇 |
1998年 | 203篇 |
1997年 | 198篇 |
1996年 | 194篇 |
1995年 | 231篇 |
1994年 | 243篇 |
1993年 | 209篇 |
1992年 | 227篇 |
1991年 | 232篇 |
1990年 | 257篇 |
1989年 | 231篇 |
1988年 | 186篇 |
1987年 | 186篇 |
1986年 | 182篇 |
1985年 | 184篇 |
1984年 | 201篇 |
1983年 | 188篇 |
1982年 | 198篇 |
1981年 | 209篇 |
1980年 | 170篇 |
1979年 | 182篇 |
1978年 | 153篇 |
1977年 | 143篇 |
1974年 | 149篇 |
1973年 | 148篇 |
1968年 | 160篇 |
1967年 | 189篇 |
1966年 | 158篇 |
1965年 | 153篇 |
1964年 | 155篇 |
1963年 | 142篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
681.
ANNA M. PIDGEON CURTIS H. FLATHER VOLKER C. RADELOFF CHRISTOPHER A. LEPCZYK NICHOLAS S. KEULER ERIC M. WOOD SUSAN I. STEWART ROGER B. HAMMER 《Conservation biology》2014,28(5):1291-1301
As people encroach increasingly on natural areas, one question is how this affects avian biodiversity. The answer to this is partly scale‐dependent. At broad scales, human populations and biodiversity concentrate in the same areas and are positively associated, but at local scales people and biodiversity are negatively associated with biodiversity. We investigated whether there is also a systematic temporal trend in the relationship between bird biodiversity and housing development. We used linear regression to examine associations between forest bird species richness and housing growth in the conterminous United States over 30 years. Our data sources were the North American Breeding Bird Survey and the 2000 decennial U.S. Census. In the 9 largest forested ecoregions, housing density increased continually over time. Across the conterminous United States, the association between bird species richness and housing density was positive for virtually all guilds except ground nesting birds. We found a systematic trajectory of declining bird species richness as housing increased through time. In more recently developed ecoregions, where housing density was still low, the association with bird species richness was neutral or positive. In ecoregions that were developed earlier and where housing density was highest, the association of housing density with bird species richness for most guilds was negative and grew stronger with advancing decades. We propose that in general the relationship between human settlement and biodiversity over time unfolds as a 2‐phase process. The first phase is apparently innocuous; associations are positive due to coincidence of low‐density housing with high biodiversity. The second phase is highly detrimental to biodiversity, and increases in housing density are associated with biodiversity losses. The long‐term effect on biodiversity depends on the final housing density. This general pattern can help unify our understanding of the relationship of human encroachment and biodiversity response. Patrones Sistemáticos Temporales en la Relación entre Desarrollos Urbanos y la Biodiversidad de Aves de Bosque 相似文献
682.
Plant conservation initiatives lag behind and receive considerably less funding than animal conservation projects. We explored a potential reason for this bias: a tendency among humans to neither notice nor value plants in the environment. Experimental research and surveys have demonstrated higher preference for, superior recall of, and better visual detection of animals compared with plants. This bias has been attributed to perceptual factors such as lack of motion by plants and the tendency of plants to visually blend together but also to cultural factors such as a greater focus on animals in formal biological education. In contrast, ethnographic research reveals that many social groups have strong bonds with plants, including nonhierarchical kinship relationships. We argue that plant blindness is common, but not inevitable. If immersed in a plant‐affiliated culture, the individual will experience language and practices that enhance capacity to detect, recall, and value plants, something less likely to occur in zoocentric societies. Therefore, conservation programs can contribute to reducing this bias. We considered strategies that might reduce this bias and encourage plant conservation behavior. Psychological research demonstrates that people are more likely to support conservation of species that have human‐like characteristics and that support for conservation can be increased by encouraging people to practice empathy and anthropomorphism of nonhuman species. We argue that support for plant conservation may be garnered through strategies that promote identification and empathy with plants. 相似文献
683.
684.
685.
‘Bringing the state back in’ to research on comparative, inter-, and trans-national environmental politics and policy will contribute to better understanding of the limits and prospects of contemporary approaches to environmental politics and the overall evolution of contemporary states once environmental issues become central. The rationale for the state as an analytical perspective in environmental policy and politics is explained, and an empirically oriented concept of the environmental state is introduced, along with a tentative sketch of its evolution in historical perspective. A research agenda on the environmental state is mapped out, centring around variation and convergence in environmental states across space and time; the political/economic dynamics of contemporary environmental states; and inter-linkages among environmental problems, the constitution of political communities, and the functioning of the public power. In conclusion, the ways in which the contributions to this volume address that research agenda are introduced. 相似文献
686.
Alexis Laurent Julie Clavreul Anna Bernstad Ioannis Bakas Monia Niero Emmanuel Gentil Thomas H. Christensen Michael Z. Hauschild 《Waste management (New York, N.Y.)》2014,34(3):589-606
Life cycle assessment (LCA) is increasingly used in waste management to identify strategies that prevent or minimise negative impacts on ecosystems, human health or natural resources. However, the quality of the provided support to decision- and policy-makers is strongly dependent on a proper conduct of the LCA. How has LCA been applied until now? Are there any inconsistencies in the past practice? To answer these questions, we draw on a critical review of 222 published LCA studies of solid waste management systems. We analyse the past practice against the ISO standard requirements and the ILCD Handbook guidelines for each major step within the goal definition, scope definition, inventory analysis, impact assessment, and interpretation phases of the methodology. Results show that malpractices exist in several aspects of the LCA with large differences across studies. Examples are a frequent neglect of the goal definition, a frequent lack of transparency and precision in the definition of the scope of the study, e.g. an unclear delimitation of the system boundaries, a truncated impact coverage, difficulties in capturing influential local specificities such as representative waste compositions into the inventory, and a frequent lack of essential sensitivity and uncertainty analyses. Many of these aspects are important for the reliability of the results. For each of them, we therefore provide detailed recommendations to practitioners of waste management LCAs. 相似文献
687.
M.A.S.S. Ravagnani M.H.M. Reis R. Maciel Filho M.R. Wolf-Maciel 《Process Safety and Environmental Protection》2010,88(1):67-73
Production of anhydrous ethanol in large scale has been made by extractive distillation using conventional solvents like ethylene-glycol. In the present paper, extractive distillation process is studied to obtain pure ethanol using ethylene-glycol and tetraethylene-glycol as solvents. Residue curve maps are used to analyse the proposed distillation processes in interpreting mixture behaviours and feasibility of distillation columns. The industrial process is simulated at steady state from residue curve map analysis. Simulation results for the ethanol/water mixture using ethylene-glycol, the conventional solvent, and tetraethylene-glycol, an alternative solvent, are presented. These results showed that the process using tetraethylene-glycol is reliable, although it requires more energy than the process with ethylene-glycol. However, ethylene-glycol has a considerable toxicity level while tetraethylene-glycol is non-toxic. 相似文献
688.
Anders Damgaard Christian Riber Thilde Fruergaard Tore Hulgaard Thomas H. Christensen 《Waste management (New York, N.Y.)》2010,30(7):1244-1250
Incineration of municipal solid waste is a debated waste management technology. In some countries it is the main waste management option whereas in other countries it has been disregarded. The main discussion point on waste incineration is the release of air emissions from the combustion of the waste, but also the energy recovery efficiency has a large importance.The historical development of air pollution control in waste incineration was studied through life-cycle-assessment modelling of eight different air pollution control technologies. The results showed a drastic reduction in the release of air emissions and consequently a significant reduction in the potential environmental impacts of waste incineration. Improvements of a factor 0.85–174 were obtained in the different impact potentials as technology developed from no emission control at all, to the best available emission control technologies of today (2010).The importance of efficient energy recovery was studied through seven different combinations of heat and electricity recovery, which were modelled to substitute energy produced from either coal or natural gas. The best air pollution control technology was used at the incinerator. It was found that when substituting coal based energy production total net savings were obtained in both the standard and toxic impact categories. However, if the substituted energy production was based on natural gas, only the most efficient recovery options yielded net savings with respect to the standard impacts. With regards to the toxic impact categories, emissions from the waste incineration process were always larger than those from the avoided energy production based on natural gas. The results shows that the potential environmental impacts from air emissions have decreased drastically during the last 35 years and that these impacts can be partly or fully offset by recovering energy which otherwise should have been produced from fossil fuels like coal or natural gas. 相似文献
689.
Patrick T.I. Lam Edwin H.W. Chan C.S. Poon C.K. Chau K.P. Chun 《Journal of environmental management》2010,91(3):654-661
Green specifications constitute one of the important elements in green construction. New sustainability requirements and changing priorities in construction management have spurred the emerging green specifications to a faster pace of development. A cross-sectional survey has been conducted in Hong Kong in 2007 to identify principal factors leading to the success of preparing green specifications. Based on extensive construction management literature, 20 variables concerning sustainable construction were summarized. Using the Mann–Whitney U-test, the subtle differences between stakeholders in specifying construction work have been detected even with the high consistency of the responses among the groups. Moreover, five independent factors for successful specification of green construction have been categorized by factor analysis. They are related to (1) green technology and techniques, (2) reliability and quality of specification, (3) leadership and responsibility, (4) stakeholder involvement, and (5) guide and benchmarking systems. Whilst the first and fourth factors are generally more important, different stakeholder groups have different emphases. The results of the survey have been validated against established principles. 相似文献
690.