全文获取类型
收费全文 | 356篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 6篇 |
环保管理 | 96篇 |
综合类 | 44篇 |
基础理论 | 100篇 |
环境理论 | 2篇 |
污染及防治 | 64篇 |
评价与监测 | 23篇 |
社会与环境 | 13篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 16篇 |
2014年 | 10篇 |
2013年 | 32篇 |
2012年 | 18篇 |
2011年 | 18篇 |
2010年 | 17篇 |
2009年 | 18篇 |
2008年 | 18篇 |
2007年 | 18篇 |
2006年 | 20篇 |
2005年 | 17篇 |
2004年 | 14篇 |
2003年 | 23篇 |
2002年 | 7篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有366条查询结果,搜索用时 15 毫秒
271.
Wetlands provide multiple ecosystem services, the sustainable use of which requires knowledge of the underlying ecological mechanisms. Functional traits, particularly the community-weighted mean trait (CWMT), provide a strong link between species communities and ecosystem functioning. We here combine species distribution modeling and plant functional traits to estimate the direction of change of ecosystem processes under climate change. We model changes in CWMT values for traits relevant to three key services, focusing on the regional species pool in the Norrström area (central Sweden) and three main wetland types. Our method predicts proportional shifts toward faster growing, more productive and taller species, which tend to increase CWMT values of specific leaf area and canopy height, whereas changes in root depth vary. The predicted changes in CWMT values suggest a potential increase in flood attenuation services, a potential increase in short (but not long)-term nutrient retention, and ambiguous outcomes for carbon sequestration. 相似文献
272.
Louise C. Ross Gunnar Austrheim Leif-Jarle Asheim Gunnar Bjarnason Jon Feilberg Anna Maria Fosaa Alison J. Hester Øystein Holand Ingibjörg S. Jónsdóttir Lis E. Mortensen Atle Mysterud Erla Olsen Anders Skonhoft James D. M. Speed Geir Steinheim Des B. A. Thompson Anna Gudrún Thórhallsdóttir 《Ambio》2016,45(5):551-566
273.
Yousheng Zeng Jon Morris Albert Sanders Srikanth Mutyala Cory Zeng 《Journal of the Air & Waste Management Association (1995)》2017,67(11):1180-1191
Response factors (RF) can be used to characterize relative sensitivity of one compound vs. another compound for the same measurement instrument. Use of RF allows the analysts/operators to calibrate the instrument with one compound and make measurement for a large number of compounds. This method is adopted for Flame Ionization Detector (FID) based survey instruments used in the Leak Detection and Repair (LDAR) practice for control of fugitive emissions of volatile organic compounds. Gas detecting Infrared (IR) cameras have been used for leak detection. However, the RF for IR cameras has not been well established despite some attempt to develop a method for IR camera RF. In addition to a method proposed earlier (Method 1), two new methods for IR camera RF are proposed in this paper: Method 2 based on theoretical approach and Method 3 based on experimental approach. All three methods are examined and compared. Both Methods 2 and 3 have shown the ability to characterize the behavior of RF for various compounds and substantially higher accuracy than Method 1. Method 2 provides a mechanism to generate RF for a large number of compounds without conducting experiments, and is recommended for implementation. The RF derived from this method can be used both in the emerging field of Quantitative Optical Gas Imaging (QOGI) and to answer the most common question that IR camera users ask—whether a particular compound can be imaged by a particular IR camera.Implications: Infrared imager is an efficient tool for detecting gas leaks from process equipment and has been used in leak detection and repair (LDAR) programs for control of fugitive emissions. However, the information regarding which chemical compounds can be imaged and how sensitive a given infrared imager is for various compounds is limited. A theoretical method is presented in this paper that can answer these questions without conducting resource-intensive experiment. The results of this theoretical method has good agreement with experimental data. The method has been used to predict relative sensitivity for 398 compounds. 相似文献
274.
Correlation of crude oils, or refined products, in the environment with suspected sources is typically undertaken through the use of GC and GCMS and in certain cases bulk carbon isotope compositions. However, with crude condensates, or refined products in particular, the absence, or low concentration, of biomarkers precludes their successful use for making unique correlations. An alternative and, sometimes, complimentary technique for correlation of such products is evolving through the use of combined gas chromatography-isotope ratio mass spectrometry (GCIRMS). This approach permits determination of the carbon and hydrogen isotopic composition of individual compounds in the crude oil or refined product to produce isotopic fingerprints for use in correlation studies. In this paper, it is proposed to review applications of GCIRMS to the correlation of various spilled products with their suspected sources in different environments. Whilst not proposing that this technique will replace GC or GCMS; it is proposed that GCIRMS is a very powerful tool to be used in conjunction with GC and GCMS to make such correlations. Although isotopic fractionation has been observed in some of the lighter components such as benzene and toluene, higher carbon numbered compounds, say above C 10 , do not appear to undergo any significant isotopic fractionation as a result of weathering. Furthermore with refined products, isotopic fractionation of the lighter components has the potential to demonstrate the onset of natural attenuation of refined products in the environment. 相似文献
275.
Shawn Burnell Jon Spitzinger Peng Jin Jay Erickson Erin Hauber Denice Nelson 《补救:环境净化治理成本、技术与工艺杂志》2013,23(1):85-101
Over the past decade, we have learned a number of critical lessons surrounding carbon substrate handling while operating and maintaining hundreds of enhanced in situ biological remedies. The same qualities that make these substrates effective can also cause biofouling of the mixing system, piping infrastructure, and remediation wells. Managing biofouling is a key piece of a successful remedy and requires a unique set of design principles. Small decreases in injection rates can have considerable impacts to life‐cycle costs and performance caused by decreased substrate distribution and longer injection time frames, resulting in the need for system cleaning, well rehabilitation, and even well replacement. Biofouling can impair performance in any size system, but effects are often magnified by large injection volumes and extended time frames. Design should be considered in all stages of the anaerobic enhanced in situ bioremediation life cycle, particularly related to reagent mixing, storage, and residence time within the system. By understanding the fundamental mechanisms of biofouling, practitioners can make operational adjustments to enhance remedy performance by considering potential biofouling controls in the design; balancing site‐specific strategy and diagnostics; and proactively adjusting and fine tuning control/prevention technology and methodology. Ultimately, a combination of chemical and physical methods may be required to operate a carbon handling system over the long term; however, the operational costs can be greatly reduced and delivery efficiency increased if these methods are understood during the design phase. © 2013 Wiley Periodicals, Inc. 相似文献
276.
Forest Fragmentation and Landscape Transformation in a Reindeer Husbandry Area in Sweden 总被引:1,自引:0,他引:1
Reindeer husbandry and forestry are two main land users in boreal forests in northern Sweden. Modern forestry has numerous
negative effects on the ground-growing and arboreal lichens that are crucial winter resources for reindeer husbandry. Using
digitized historical maps, we examined changes in the forest landscape structure during the past 100 years, and estimated
corresponding changes in suitability of forest landscape mosaics for the reindeer winter grazing. Cover of old coniferous
forests, a key habitat type of reindeer herding system, showed a strong decrease during the study period, whereas clear-cutting
and young forests increased rapidly in the latter half of the 20th century. The dominance of young forests and fragmentation
of old-growth forests (decreased patch sizes and increased isolation) reflect decreased amount of arboreal lichens as well
as a lowered ability of the landscape to sustain long-term persistence of lichens. The results further showed that variation
in ground lichen cover among sites was mainly related to soil moisture conditions, recent disturbances, such as soil scarification
and prescribed burning, and possibly also to forest history. In general, the results suggest that the composition and configuration
of the forest landscape mosaic has become less suitable for sustainable reindeer husbandry. 相似文献
277.
Native Perennial Forb Variation Between Mountain Big Sagebrush and Wyoming Big Sagebrush Plant Communities 总被引:1,自引:0,他引:1
Big sagebrush (Artemisia tridentata Nutt.) occupies large portions of the western United States and provides valuable wildlife habitat. However, information
is lacking quantifying differences in native perennial forb characteristics between mountain big sagebrush [A. tridentata spp. vaseyana (Rydb.) Beetle] and Wyoming big sagebrush [A. tridentata spp. wyomingensis (Beetle & A. Young) S.L. Welsh] plant communities. This information is critical to accurately evaluate the quality of habitat
and forage that these communities can produce because many wildlife species consume large quantities of native perennial forbs
and depend on them for hiding cover. To compare native perennial forb characteristics on sites dominated by these two subspecies
of big sagebrush, we sampled 106 intact big sagebrush plant communities. Mountain big sagebrush plant communities produced
almost 4.5-fold more native perennial forb biomass and had greater native perennial forb species richness and diversity compared
to Wyoming big sagebrush plant communities (P < 0.001). Nonmetric multidimensional scaling (NMS) and the multiple-response permutation procedure (MRPP) demonstrated that
native perennial forb composition varied between these plant communities (P < 0.001). Native perennial forb composition was more similar within plant communities grouped by big sagebrush subspecies
than expected by chance (A = 0.112) and composition varied between community groups (P < 0.001). Indicator analysis did not identify any perennial forbs that were completely exclusive and faithful, but did identify
several perennial forbs that were relatively good indicators of either mountain big sagebrush or Wyoming big sagebrush plant
communities. Our results suggest that management plans and habitat guidelines should recognize differences in native perennial
forb characteristics between mountain and Wyoming big sagebrush plant communities. 相似文献
278.
Boreal forests in Sweden are exploited in a number of ways, including forestry and reindeer husbandry. In the winter, reindeer
feed mainly on lichens, and lichen-rich forests are a key resource in the herding system. Commercial forestry has mainly negative
effects on reindeer husbandry, and conflicts between these two industries have escalated over the last century. This article
reviews the effects of modern forest management practices on the winter resources available for reindeer husbandry. Forestry
affects reindeer husbandry at both the stand level and the landscape level and over various time scales. Clear-cutting, site
preparation, fertilization, short rotation times, and forest fragmentation have largely resulted in a reduced amount of ground
growing and arboreal lichens and restricted access to resource. This article also discusses alternative forestry practices
and approaches that could reduce the impacts of forestry on reindeer husbandry, both in the short and long term. 相似文献
279.
Ralph E. Baumgardner Jr. Selma S. Isil Jon J. Bowser Kelley M. Fitzgerald 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1266-1279
ABSTRACT The Clean Air Status and Trends Network (CASTNet) was implemented by the U.S. Environmental Protection Agency (EPA) in 1991 in response to Title IX of the Clean Air Amendments of 1990, which mandated the deployment of a national ambient air monitoring network to track progress of the implementation of emission reduction programs in terms of deposition, air quality, and changes to affected ecosystems. CASTNet evolved from the National Dry Deposition Network (NDDN). CASTNet currently consists of 45 sites in the eastern United States and 28 sites in the West. Each site measures sulfur dioxide (SO2), nitric acid (HNO3), particle sulfate (SO4 =), particle nitrate (NO3 - ), and ozone. Nineteen sites collect precipitation samples. NDDN/CASTNet uses a uniform set of site-selection criteria which provides the data user with consistent measures to compare each site. These criteria also ensure that, to the extent possible, CASTNet sites are located away from local emission sources. This paper presents an analysis of SO2 and SO4 = concentration data collected from 1987 through 1996 at rural NDDN/CASTNet sites. Annual and seasonal variability is examined. Gradients of SO2 and SO4 = are discussed. The variability of the atmospheric mix of SO2 and SO4 = is explored spatially and seasonally. Data from CASTNet are also compared to SO2 and SO4 = data from concurrent monitoring studies in rural areas. 相似文献
280.
In this paper, a simple model for analysing variability in radon concentrations in homes is tested. The approach used here involves two error components, representing additive and multiplicative errors, together with variation between-houses. We use a Bayesian approach for our analysis and apply this model to two datasets of repeat radon measurements in homes; one based on 3-month long measurements for which the original measurements were close to the current UK Radon Action Level (200 Bq m−3), and the other based on 6-month measurement data (from regional and national surveys), for which the original measurements cover a wide range of radon concentrations, down to very low levels. The model with two error components provides a better fit to these datasets than does a model based on solely multiplicative errors. 相似文献