全文获取类型
收费全文 | 4047篇 |
免费 | 70篇 |
国内免费 | 36篇 |
专业分类
安全科学 | 227篇 |
废物处理 | 129篇 |
环保管理 | 1054篇 |
综合类 | 382篇 |
基础理论 | 997篇 |
环境理论 | 8篇 |
污染及防治 | 893篇 |
评价与监测 | 272篇 |
社会与环境 | 151篇 |
灾害及防治 | 40篇 |
出版年
2023年 | 16篇 |
2022年 | 25篇 |
2021年 | 35篇 |
2020年 | 31篇 |
2019年 | 43篇 |
2018年 | 55篇 |
2017年 | 76篇 |
2016年 | 97篇 |
2015年 | 84篇 |
2014年 | 93篇 |
2013年 | 482篇 |
2012年 | 148篇 |
2011年 | 208篇 |
2010年 | 136篇 |
2009年 | 153篇 |
2008年 | 177篇 |
2007年 | 221篇 |
2006年 | 159篇 |
2005年 | 140篇 |
2004年 | 146篇 |
2003年 | 143篇 |
2002年 | 118篇 |
2001年 | 77篇 |
2000年 | 87篇 |
1999年 | 59篇 |
1998年 | 61篇 |
1997年 | 52篇 |
1996年 | 69篇 |
1995年 | 64篇 |
1994年 | 72篇 |
1993年 | 59篇 |
1992年 | 52篇 |
1991年 | 45篇 |
1990年 | 44篇 |
1989年 | 36篇 |
1988年 | 46篇 |
1987年 | 39篇 |
1986年 | 41篇 |
1985年 | 35篇 |
1984年 | 39篇 |
1983年 | 42篇 |
1982年 | 50篇 |
1981年 | 53篇 |
1980年 | 26篇 |
1979年 | 33篇 |
1978年 | 26篇 |
1977年 | 35篇 |
1976年 | 15篇 |
1974年 | 11篇 |
1972年 | 13篇 |
排序方式: 共有4153条查询结果,搜索用时 31 毫秒
951.
All U.S. federal agencies administering environmental laws purport to practice adaptive management (AM), but little is known about how they actually implement this conservation tool. A gap between the theory and practice of AM is revealed in judicial decisions reviewing agency adaptive management plans. We analyzed all U.S. federal court opinions published through 1 January 2015 to identify the agency AM practices courts found most deficient. The shortcomings included lack of clear objectives and processes, monitoring thresholds, and defined actions triggered by thresholds. This trio of agency shortcuts around critical, iterative steps characterizes what we call AM‐lite. Passive AM differs from active AM in its relative lack of management interventions through experimental strategies. In contrast, AM‐lite is a distinctive form of passive AM that fails to provide for the iterative steps necessary to learn from management. Courts have developed a sophisticated understanding of AM and often offer instructive rather than merely critical opinions. The role of the judiciary is limited by agency discretion under U.S. administrative law. But courts have overturned some agency AM‐lite practices and insisted on more rigorous analyses to ensure that the promised benefits of structured learning and fine‐tuned management have a reasonable likelihood of occurring. Nonetheless, there remains a mismatch in U.S. administrative law between the flexibility demanded by adaptive management and the legal objectives of transparency, public participation, and finality. 相似文献
952.
953.
Mert Guney Robert P. Chapuis Gerald J. Zagury 《Environmental science and pollution research international》2016,23(24):24422-24434
Human exposure to particulate matter (PM) has been associated with adverse health effects. While inhalation exposure to airborne PM is a prominent research subject, exposure to PM of geological origin (i.e., generated from soil/soil-like material) has received less attention. This review discusses the contaminants in PM of geological origin and their relevance for human exposure and then evaluates lung bioaccessibility assessment methods and their use. PM of geological origin can contain toxic elements as well as organic contaminants. Observed/predicted PM lung clearance times are long, which may lead to prolonged contact with lung environment. Thus, certain exposure scenarios warrant the use of in vitro bioaccessibility testing to predict lung bioavailability. Limited research is available on lung bioaccessibility test development and test application to PM of geological origin. For in vitro tests, test parameter variation between different studies and concerns about physiological relevance indicate a crucial need for test method standardization and comparison with relevant animal data. Research is recommended on (1) developing robust in vitro lung bioaccessibility methods, (2) assessing bioaccessibility of various contaminants (especially polycyclic aromatic hydrocarbons (PAHs)) in PM of diverse origin (surface soils, mine tailings, etc.), and (3) risk characterization to determine relative importance of exposure to PM of geological origin. 相似文献
954.
Modeling freshwater fish distributions using multiscale landscape data: A case study of six narrow range endemics 总被引:1,自引:0,他引:1
Species distribution models (SDMs) have become integral tools in scientific research and conservation planning. Despite progress in the assessment of various statistical models for use in SDMs, little has been done in way of evaluating appropriate ecological models. In this paper, we evaluate the multiscale filter framework as a suitable theoretical model for predicting freshwater fish distributions in the upper Green River system (Ohio River drainage), USA. The spatial distributions of six fishes with contrasting biogeographies were modeled using boosted regression trees and multiscale landscape data. Species biogeography did not appear to affect predictive performance and all models performed well statistically with receiver operating characteristic area under the curve (AUC) ranging from 0.87 to 0.98. Predictive maps show accurate estimations of ranges for five of six species based on historical collections. The relative influence of each type of environmental feature and spatial scale varied markedly with between species. A hierarchical effect was detected for narrowly distributed species. These species were highly influenced by soil composition at larger spatial scales and land use/land cover (LULC) patterns at more proximal scales. Conversely, LULC pattern was the most influential feature for widely distributed at all spatial scales. Using multiscale data capable of capturing hierarchical landscape influences allowed production of accurate predictive models and provided further insight into factors controlling freshwater fish distributions. 相似文献
955.
956.
Jerome J. Schleier III Collin Preftakes Robert K. D. Peterson 《Journal of environmental science and health. Part. B》2013,48(7):621-625
The most important factor affecting efficacy and drift of pesticide applications is the droplet spectrum. To measure pesticide drift, researchers utilize fluorescent tracers to rapidly quantify spray deposition. Although fluorescent tracers have been used for more than 50 years, no experiments have been performed on the effect they have on the properties of pesticide formulations (density and viscosity) or droplet spectrum, which affect the drift of pesticides. Therefore, we examined the effect of an oil- and water-based tracer on the volume median diameter (VMD), viscosity, and density of oil- and water-based pesticide formulations. In addition, we experimentally fit and demonstrate the utility of using distributions to characterize pesticide droplet spectra. The addition of tracers to both water- and oil-based formulations did not significantly alter the VMD, viscosity, and density. Lognormal distributions provided the best fit for the water- and oil-based formulations with and without tracer. Our results demonstrated that the addition of oil- and water-based tracers do not significantly alter pesticide formulations properties and droplet spectrum, and most likely do not alter the movement of pesticide droplets in the environment. 相似文献
957.
958.
James J. Lavelle Joel Brockner Mary A. Konovsky Kenneth H. Price Amy B. Henley Aakash Taneja Vishnu Vinekar 《组织行为杂志》2009,30(3):337-357
Research on commitment, procedural fairness, and organizational citizenship behavior (OCB) suggests that employees maintain distinct beliefs about, and direct behaviors towards, multiple targets in the workplace (e.g., the organization as a whole, their supervisor, and fellow workgroup members). The present studies were designed to test for “target similarity effects,” in which the relationships between commitment, procedural fairness, and OCB were expected to be stronger when they referred to the same target than when they referred to different targets. As predicted, we found that: (1) the positive relationship between commitment and OCB, and (2) the mediating effect of commitment on the positive relationship between procedural fairness and OCB, was particularly likely to emerge when the constructs were in reference to the same target. Support for these target similarity effects was found among layoff survivors (Study 1) and student project teams (Study 2). Theoretical and practical implications are discussed, as are limitations of the studies and suggestions for future research. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
959.
Liem T. Tran C. Gregory Knight Robert V. O'Neill Elizabeth R. Smith Kurt H. Riitters James Wickham 《Environmental management》2001,29(6):845-859
A fuzzy decision analysis method for integrating ecological indicators was developed. This was a combination of a fuzzy ranking method and the analytic hierarchy process (AHP). The method was capable of ranking ecosystems in terms of environmental conditions and suggesting cumulative impacts across a large region. Using data on land cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic region, we were able to point out areas that were in relatively poor condition and/or vulnerable to future deterioration. The method offered an easy and comprehensive way to combine the strengths of fuzzy set theory and the AHP for ecological assessment. Furthermore, the suggested method can serve as a building block for the evaluation of environmental policies. 相似文献
960.
Ashlee E. Walker Robert E. Holman Ross B. Leidy 《Journal of the American Water Resources Association》2000,36(1):67-74
ABSTRACT: Studies were conducted to analyze the presence of 11 pesticide residues in 12 surface waters in the Piedmont and coastal plain regions of North Carolina. Samples were assayed using enzyme‐linked immunosorbent assays (ELISAs). All ELISA results of one part per billion (ppb, μg/L) or greater were confirmed using gas chromatography/mass spectrometry (GCIMS). ELISA detection limits were approximately an order of magnitude higher than GCJMS methods. Of the 5,035 analytical results from 742 surface water samples, atrazine was detected in approximately 45 percent of the samples, five of which were at or above the Maximum Contaminant Level (MCL) of 3‐ppb. Metolachlor was detected in 64 percent of the samples. Aldicarb, 2,4‐D, chlorpyrifos, and chlorothalonil were also detected, and each was found in less than 12 percent of the samples. The remaining pesticides, including carbaryl, acetochior, methomyl, carbofuran, and alachlor, were not detected during the study period. 相似文献