全文获取类型
收费全文 | 1019篇 |
免费 | 10篇 |
国内免费 | 16篇 |
专业分类
安全科学 | 43篇 |
废物处理 | 38篇 |
环保管理 | 122篇 |
综合类 | 190篇 |
基础理论 | 170篇 |
环境理论 | 1篇 |
污染及防治 | 349篇 |
评价与监测 | 70篇 |
社会与环境 | 47篇 |
灾害及防治 | 15篇 |
出版年
2023年 | 20篇 |
2022年 | 23篇 |
2021年 | 34篇 |
2020年 | 27篇 |
2019年 | 23篇 |
2018年 | 48篇 |
2017年 | 48篇 |
2016年 | 57篇 |
2015年 | 37篇 |
2014年 | 60篇 |
2013年 | 72篇 |
2012年 | 61篇 |
2011年 | 81篇 |
2010年 | 52篇 |
2009年 | 42篇 |
2008年 | 63篇 |
2007年 | 58篇 |
2006年 | 63篇 |
2005年 | 44篇 |
2004年 | 34篇 |
2003年 | 18篇 |
2002年 | 18篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 7篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1966年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1954年 | 3篇 |
1951年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有1045条查询结果,搜索用时 15 毫秒
211.
The main objective of this study is to quantify the potential overpressures due to Vapor Cloud Explosions (VCEs) and the potential gas buildup by using Computation Fluid Dynamics (CFD) for onshore or offshore facilities.A series of CFD simulations and analyses have been performed for the various vapor dispersion scenarios, covering different release rates and release locations. The overpressure that could result from the potential VCE is assessed by CFD simulation for the largest explosive transient gas cloud. The results from the analyses also comprise an extensive picture of probable leak scenarios having the potential to make an explosive gas cloud.The CFD analysis results could be applied to provide input for detailed risk-based design and risk analysis, to find safe and cost-optimal design against explosions. 相似文献
212.
Metal distribution and stability in constructed wetland sediment 总被引:2,自引:0,他引:2
Knox AS Paller MH Nelson EA Specht WL Halverson NV Gladden JB 《Journal of environmental quality》2006,35(5):1948-1959
The A-01 wetland treatment system (WTS) is a surface flow wetland planted with giant bulrush [Schoenoplectus californicus (C.A. Mey.) Palla] that is designed to remove Cu and other metals from the A-01 National Pollution Discharge Elimination System (NPDES) effluent at the Savannah River Site near Aiken, SC. Copper, Zn, and Pb concentrations in water were usually reduced 60 to 80% by passage through the treatment system. The Cu concentrations in the wetland sediments increased from about 4 to 205 and 796 mg kg(-1), respectively, in the organic and floc sediment layers in cell 4A over a 5-yr period. Metal concentrations were higher in the two top layers of sediment (i.e., the floc and organic layers) than in the deeper inorganic layers. Sequential extraction was used to evaluate remobilization and retention of Cu, Pb, Zn, Mn, and Fe in the wetland sediment. Metal remobilization was determined by the potentially mobile fraction (PMF) and metal retention by the recalcitrant factor (RF). The PMF values were high in the floc layer but comparatively low in the organic and inorganic layers. High RF values for Cu, Zn, and Pb in the organic and inorganic layers indicated that these metals were strongly bound in the sediment. The RF values for Mn were lower than for the other elements especially in the floc layer, indicating low retention or binding capacity. Retention of contaminants was also evaluated by distribution coefficient (Kd) values. Distribution coefficient (Kd) values were lower for Cu and Zn than for Pb, indicating a smaller exchangeable fraction for Pb. 相似文献
213.
214.
Quantifying species recovery and conservation success to develop an IUCN Green List of Species
下载免费PDF全文
![点击此处可从《Conservation biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
H. Resit Akçakaya Elizabeth L. Bennett Thomas M. Brooks Molly K. Grace Anna Heath Simon Hedges Craig Hilton‐Taylor Michael Hoffmann David A. Keith Barney Long David P. Mallon Erik Meijaard E.J. Milner‐Gulland Ana S.L. Rodrigues Jon Paul Rodriguez P.J. Stephenson Simon N. Stuart Richard P. Young 《Conservation biology》2018,32(5):1128-1138
Stopping declines in biodiversity is critically important, but it is only a first step toward achieving more ambitious conservation goals. The absence of an objective and practical definition of species recovery that is applicable across taxonomic groups leads to inconsistent targets in recovery plans and frustrates reporting and maximization of conservation impact. We devised a framework for comprehensively assessing species recovery and conservation success. We propose a definition of a fully recovered species that emphasizes viability, ecological functionality, and representation; and use counterfactual approaches to quantify degree of recovery. This allowed us to calculate a set of 4 conservation metrics that demonstrate impacts of conservation efforts to date (conservation legacy); identify dependence of a species on conservation actions (conservation dependence); quantify expected gains resulting from conservation action in the medium term (conservation gain); and specify requirements to achieve maximum plausible recovery over the long term (recovery potential). These metrics can incentivize the establishment and achievement of ambitious conservation targets. We illustrate their use by applying the framework to a vertebrate, an invertebrate, and a woody and an herbaceous plant. Our approach is a preliminary framework for an International Union for Conservation of Nature (IUCN) Green List of Species, which was mandated by a resolution of IUCN members in 2012. Although there are several challenges in applying our proposed framework to a wide range of species, we believe its further development, implementation, and integration with the IUCN Red List of Threatened Species will help catalyze a positive and ambitious vision for conservation that will drive sustained conservation action. 相似文献
215.
Antonio Scipioni Michele Mastrobuono Anna Mazzi Alessandro Manzardo 《Journal of Cleaner Production》2010,18(4):299-306
Voluntary GHG management is a primary issue for many organizations. To support organizations with this activity, authoritative bodies have published many different guidelines. Nevertheless, these guidelines show limitations in identification of the direct and indirect processes that have a major impact on climate change, which should be considered in GHG management.In this paper, a life cycle approach is used to identify the processes of an organization and its supply chain that have major impacts on climate change. The results show that this approach is compatible with the current ISO standards and that in the case study the greatest emissions come from the organization’s indirect processes. 相似文献
216.
217.
Assessment of the environmental significance of heavy metal pollution in surficial sediments of the River Po 总被引:13,自引:0,他引:13
The magnitude and ecological relevance of metal pollution of the middle Po river deriving from the River Lambro tributary was investigated by applying different (complementary) sediment quality assessment approaches: (1) comparisons of concentrations with regional reference data, and (2) comparisons with consensus-based sediment quality guidelines (SQGs), as well as by investigations of the partitioning patterns of target heavy metals (Cd, Cu, Ni, Pb, Zn). Total metal concentrations in the surficial sediments revealed significant pollution inputs on the whole river stretch investigated, with a distinct peak at the inlet of the River Lambro. Based on the geoaccumulation index of target heavy metals, the middle reach of River Po has to be considered as moderately polluted with Cd (1相似文献
218.
Jennifer M. Jandt Eden Huang Anna Dornhaus 《Behavioral ecology and sociobiology》2009,63(12):1829-1836
Division of labor is common across social groups. In social insects, many studies focus on the differentiation of in-nest
and foraging workers and/or the division of foraging tasks. Few studies have specifically examined how workers divide in-nest
tasks. In the bumble bee, Bombus impatiens, we have shown previously that smaller workers are more likely to feed larvae and incubate brood, whereas larger workers
are more likely to fan or guard the nest. Here, we show that in spite of this, B. impatiens workers generally perform multiple tasks throughout their life. The size of this task repertoire size does not depend on
body size, nor does it change with age. Further, individuals were more likely to perform the task they had been performing
on the previous day than any other task, a pattern most pronounced among individuals who guarded the nest. On the other hand,
there was no predictable sequence of task switching. Because workers tend to remain in the same region of the nest over time,
in-nest workers may concentrate on a particular task, or subset of tasks, inside that region. This division of space, then,
may be an important mechanism that leads to this weak specialization among in-nest bumble bee workers. 相似文献
219.
Anna Kärrman Kouji H. Harada Kayoko Inoue Takumi Takasuga Etsumasa Ohi Akio Koizumi 《Environment international》2009,35(4):712-717
Daily dietary intake of perfluorinated chemicals (PFCs) in relation to serum levels was assessed by determination of nine PFCs including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in matched daily diet duplicates and serum samples. Diet and serum were collected in year 2004 from 20 women in Osaka and Miyagi, Japan. Only PFOS and PFOA were detected in the diet samples and no significant difference between cities was seen. After adjusted by water content, diet concentration of PFOA was significantly higher in Osaka. The median daily intake calculated using the measured diet concentrations was 1.47 ng PFOS/kg b.w. and 1.28 ng PFOA/kg b.w. for Osaka, and 1.08 ng PFOS/kg b.w. and 0.72 ng PFOA/kg b.w. for Miyagi. A significant difference between cities was seen for the serum concentrations with median of 31 ng/mL PFOS and PFOA in Osaka, compared to 14 ng/mL PFOS and 4.6 ng/mL PFOA in Miyagi. Carboxylates such as perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUnDA) were also detected in serum at median levels 6.9 ng/mL and 3.2 ng/mL (Osaka), and 2.8 ng/mL and 5.1 ng/mL (Miyagi). Based on one-compartment model under steady state, dietary intake of PFOS and PFOA accounted for only 22.4% and 23.7% of serum levels in Osaka females, and in contrast 92.5% and 110.6% in Miyagi females, respectively. 相似文献
220.
Anna Bozzano Patricia M. Pankhurst Natalie A. Moltschaniwskyj Roger Villanueva 《Marine Biology》2009,156(7):1359-1373
Eye development, optical properties and photomechanical responses were examined in embryos and hatchlings of the southern
calamary, Sepioteuthis australis. This species occurs in shallow coastal waters in Australia and New Zealand, and the egg masses were collected in October
and December 2004 from Great Oyster Bay, Tasmania. At the earliest developmental stage the eye of the squid was comprised
of a hemispherical cup of undifferentiated neural retina, while presumptive iris cell layers and lentigenic precursor cells
enclosed a posterior eye chamber. Differentiation of the proximal and distal processes was observed in correspondence with
the cornea development and lens crystallization, and occurred before differentiation of the neural retina, which was complete
prior to hatching. Longer photoreceptor distal processes were first observed just prior to hatching in the dorsal-posterior
retina. After hatching, this difference was much more evident and higher photoreceptor density was found in the central retina.
This indicates that the eye of S. australis at this age uses different retina areas for different visual tasks. Optical sensitivity and resolution suggest that juvenile
S. australis are diurnal. This study also found functional photomechanical responses of visual screening pigment migration and pupil constriction
in S. australis embryos, although complete functionality of the pupil at this stage was uncertain. However, the pupils of squid aged 2 days
closed almost completely under bright conditions, showing that photomechanical responses were highly developed in the juvenile
squid. These findings indicate that squid embryos are able to perceive visual stimulation, suggesting an early reliance on
vision for survival after hatching. 相似文献