全文获取类型
收费全文 | 4059篇 |
免费 | 101篇 |
国内免费 | 53篇 |
专业分类
安全科学 | 253篇 |
废物处理 | 155篇 |
环保管理 | 838篇 |
综合类 | 476篇 |
基础理论 | 1012篇 |
环境理论 | 3篇 |
污染及防治 | 954篇 |
评价与监测 | 313篇 |
社会与环境 | 168篇 |
灾害及防治 | 41篇 |
出版年
2023年 | 28篇 |
2022年 | 40篇 |
2021年 | 46篇 |
2020年 | 57篇 |
2019年 | 72篇 |
2018年 | 86篇 |
2017年 | 124篇 |
2016年 | 143篇 |
2015年 | 109篇 |
2014年 | 134篇 |
2013年 | 352篇 |
2012年 | 187篇 |
2011年 | 237篇 |
2010年 | 184篇 |
2009年 | 206篇 |
2008年 | 210篇 |
2007年 | 221篇 |
2006年 | 206篇 |
2005年 | 178篇 |
2004年 | 156篇 |
2003年 | 138篇 |
2002年 | 136篇 |
2001年 | 97篇 |
2000年 | 69篇 |
1999年 | 64篇 |
1998年 | 48篇 |
1997年 | 64篇 |
1996年 | 50篇 |
1995年 | 55篇 |
1994年 | 57篇 |
1993年 | 46篇 |
1992年 | 39篇 |
1991年 | 31篇 |
1990年 | 29篇 |
1989年 | 29篇 |
1988年 | 23篇 |
1987年 | 17篇 |
1986年 | 17篇 |
1985年 | 23篇 |
1984年 | 18篇 |
1983年 | 28篇 |
1982年 | 22篇 |
1981年 | 33篇 |
1980年 | 19篇 |
1979年 | 19篇 |
1978年 | 13篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1972年 | 5篇 |
排序方式: 共有4213条查询结果,搜索用时 937 毫秒
271.
Jeffrey J. Opperman Ryan Luster Bruce A. McKenney Michael Roberts Amanda Wrona Meadows 《Journal of the American Water Resources Association》2010,46(2):211-226
Opperman, Jeffrey J., Ryan Luster, Bruce A. McKenney, Michael Roberts, and Amanda Wrona Meadows, 2010. Ecologically Functional Floodplains: Connectivity, Flow Regime, and Scale. Journal of the American Water Resources Association (JAWRA) 46(2):211-226. DOI: 10.1111/j.1752-1688.2010.00426.x Abstract: This paper proposes a conceptual model that captures key attributes of ecologically functional floodplains, encompassing three basic elements: (1) hydrologic connectivity between the river and the floodplain, (2) a variable hydrograph that reflects seasonal precipitation patterns and retains a range of both high and low flow events, and (3) sufficient spatial scale to encompass dynamic processes and for floodplain benefits to accrue to a meaningful level. Although floodplains support high levels of biodiversity and some of the most productive ecosystems on Earth, they are also among the most converted and threatened ecosystems and therefore have recently become the focus of conservation and restoration programs across the United States and globally. These efforts seek to conserve or restore complex, highly variable ecosystems and often must simultaneously address both land and water management. Thus, such efforts must overcome considerable scientific, technical, and socioeconomic challenges. In addition to proposing a scientific conceptual model, this paper also includes three case studies that illustrate methods for addressing these technical and socioeconomic challenges within projects that seek to promote ecologically functional floodplains through river-floodplain reconnection and/or restoration of key components of hydrological variability. 相似文献
272.
Michael M. Pollock Timothy J. Beechie 《Journal of the American Water Resources Association》2010,46(4):843-847
Pollock, Michael M. and Timothy J. Beechie, 2010. Reply to Discussion –“Stream Temperature Relationships to Forest Harvest in Western Washington” by George Ice, George Brown, John Gravelle, C. Rhett Jackson, Jeff Light, Timothy Link, Douglas Martin, Dale McGreer, and Arne Skaugset. Journal of the American Water Resources Association (JAWRA) 46(4): 843-847. DOI: 10.1111/j.1752-1688.2010.00456.x 相似文献
273.
Jason G. Su Michael Jerrett Bernardo Beckerman Dave Verma M. Altaf Arain Pavlos Kanaroglou Dave Stieb Murray Finkelstein Jeffery Brook 《Atmospheric environment (Oxford, England : 1994)》2010,44(29):3529-3537
More than 25 studies have employed land use regression (LUR) models to estimate nitrogen oxides and to a lesser extent particulate matter indicators, but these methods have been less commonly applied to ambient concentrations of volatile organic compounds (VOCs). Some VOCs have high plausibility as sources of health effects and others are specific indicators of motor vehicle exhaust. We used LUR models to estimate spatial variability of VOCs in Toronto, Canada. Benzene, n-hexane and total hydrocarbons (THC) were measured from July 25 to August 9, 2006 at 50 locations using the TraceAir organic vapor monitors. Nitrogen dioxide (NO2) was also sampled to assess its spatial pattern agreement with VOC exposures. Buffers for land use, population density, traffic density, physical geography, and remote sensing measures of greenness and surface brightness were also tested. The remote sensing measures have the highest correlations with VOCs and NO2 levels (i.e., explains >36% of the variance). Our regression models explain 66–68% of the variance in the spatial distribution of VOCs, compared to 81% for the NO2 model. The ranks of agreement between various VOCs range from 48 to 63% and increases substantially – up to 75% – for the top and bottom quartile groups. Agreements between NO2 and VOCs are much smaller with an average rank of 36%. Future epidemiologic studies may therefore benefit from using VOCs as potential toxic agents for traffic-related pollutants. 相似文献
274.
Jorge Pey Andrés Alastuey Xavier Querol Noemí Pérez Michael Cusack 《Atmospheric environment (Oxford, England : 1994)》2010,44(39):5112-5121
The present work shows a straightforward procedure to indirectly estimate the chemical composition at a given site only from the determination of the PM concentrations, and the classification of the days according to the main meteorological scenarios. A previous study based on the mean chemical composition associated to the main meteorological scenarios is required.This experiment has been carried out with data from two monitoring sites in the North-Western Mediterranean, one regional and one suburban background. At both sites, one-year datasets on chemical PM10 composition were obtained. Based on these datasets, the mean PM10 compositions according to the most relevant meteorological situations were calculated for both locations. After that, the reconstruction of the chemical composition for all the days with available PM10 concentrations was completed. Subsequently, the estimated PM10 composition was compared with that determined experimentally. The comparison between the rebuilt and the experimental results was very satisfactory in the case of the regional background site, and relatively replaced in the other case. Furthermore, the validation of the method at the regional background site has been conducted from the reconstruction of a 4-year data base, and subsequent comparison with the experimental chemical composition.Our results show that it is possible to attain a good approach to the chemical composition at regional background sites, where local emission sources are negligible. Conversely, when the local sources rise in importance, i.e., at a suburban background site, the approach is suitable only for those components with a more regional origin and/or those from long range transport of air masses. 相似文献
275.
The activity concentrations of Beryllium-7 (7Be), a naturally occurring radioisotope produced in the atmosphere, were measured in leaves of birch-trees, above-ground parts of grass, soil and rainwater in the mountain massive Kralicky Sneznik (the northeast of the Czech Republic, altitude about 750 m) in the years of 2005, 2006 and 2007. Dried and ground samples of the plants and soils, and water samples from wet deposition were used to determine the 7Be content using a semiconductor gamma spectrometer. The 7Be values ranged from 147.0 to 279.6 Bq kg−1, from 48.7 to 740.8 Bq kg−1, from 2.1 to 8.7 Bq kg−1, and from 0.6 to 1.9 Bq kg−1 in birch-tree leaves, grass samples, soils, and rainwater, respectively. Insignificant inter-annual variations but significant increase in the 7Be activity concentrations during the spring and summer months were observed in birch-tree leaves and grass samples. The seasonal variation of the 7Be concentrations in grass samples correlated (R2 = 0.4663 and 0.6489) with precipitation. No similar correlation was found for 7Be in birch-tree leaves. Beryllium-7 content in birch-tree leaves and in aerial parts of grass was mainly caused by direct transport of 7Be from wet deposition into aerial parts of the observed plants. 相似文献
276.
Shahbeg S. Sandhu Michael D. Waters 《Journal of environmental science and health. Part. B》2013,48(6):929-948
Abstract Over the last few decades, the use of chemical pesticides has increased dramatically in the U.S. This relatively sudden increase greatly concerns the U.S. Environmental Protection Agency (EPA), since it has the responsibility for ensuring the safety of all pesticides used in the U.S. In response to this concern, EPA has established a review program, the Rebuttable Presumption Against Registration (RPAR), for periodically reassessing the mutagenic and carcinogenic potential of pesticide compounds. This paper presents a review and evaluation of the data reported in the literature on six chemical pesticides suspect for mutagenic potential. The pesticide chemicals discussed are maleic hydrazide; rotenone; monuron; diallate; triallate, and benomyl. 相似文献
277.
Richard M. Engeman Kathy J. Couturier Rodney K. Felix Jr. Michael L. Avery 《Environmental science and pollution research international》2013,20(6):4093-4098
Feral swine are well known as environmentally destructive invasive animals in many areas around the world, where they degrade native habitats, harm rare plant and animal species, damage agricultural interests, and spread disease. We provide the first quantification of their potential as agents of disturbance at archaeological sites. Our study was conducted in south-central Florida at Avon Park Air Force Range, a base comprising over 40,000 ha and containing many archaeological sites. To determine the identifiable prevalence of feral swine disturbance, we examined 36 sites registered with the Florida State Historic Preservation Office and also eligible for inclusion in the National Register of Historic Places (NRHP). Moreover, we evaluated the extent of swine disturbance at a prehistoric site of extraordinary significance to Florida’s prehistory, “Dead Cow.” Fifteen of the 36 NRHP-eligible sites (42 %) had some level of swine disturbance, including 14 of 30 (47 %) sites known to have artifacts within 20 cm of the surface (well within swine rooting depths). At the Dead Cow site, we documented disturbance at 74 % of shovel test points. Sites with shallow artifact depositions appeared highly vulnerable to disturbance by feral swine, threatening destruction of artifact stratigraphy and provenience. Our observations likely are a minimal representation of accumulated damage. These irreplaceable sites tell the area’s land use story across the millennia. That they are under threat from feral swine should serve broad notice of potential threats that feral swine may pose to archaeological sites globally, making effective swine management imperative for site protection. 相似文献
278.
Mirco Bundschuh Michael C. Newman Jochen P. Zubrod Frank Seitz Ricki R. Rosenfeldt Ralf Schulz 《Environmental science and pollution research international》2013,20(10):7341-7347
Although generally misunderstood, the p value is the probability of the test results or more extreme results given H0 is true: it is not the probability of H0 being true given the results. To obtain directly useful insight about H0, the positive predictive value (PPV) and the negative predictive value (NPV) may be useful extensions of null hypothesis significance testing (NHST). They provide information about the probability of statistically significant and non-significant test outcomes being true based on an a priori defined biologically meaningful effect size. The present study explores the utility of PPV and NPV in an ecotoxicological context by using the frequently applied Daphnia magna reproduction test (OECD guideline 211) and the chemical stressor lindane as a model system. The results indicate that especially the NPV deviates meaningfully between a test design strictly following the guideline and an experimental procedure controlling for α and β at the level of 0.05. Consequently, PPV and NPV may be useful supplements to NHST that inform the researcher about the level of confidence warranted by both statistically significant and non-significant test results. This approach also reinforces the value of considering α, β, and a biologically meaningful effect size a priori. 相似文献
279.
Roman Seidl Fridolin Simon Brand Michael Stauffacher Pius Krütli Quang Bao Le Andy Spörri Grégoire Meylan Corinne Moser Monica Berger González Roland Werner Scholz 《Ambio》2013,42(1):5-12
Interdisciplinary scientific knowledge is necessary but not sufficient when it comes to addressing sustainable transformations, as science increasingly has to deal with normative and value-related issues. A systems perspective on coupled human–environmental systems (HES) helps to address the inherent complexities. Additionally, a thorough interaction between science and society (i.e., transdisciplinarity = TD) is necessary, as sustainable transitions are sometimes contested and can cause conflicts. In order to navigate complexities regarding the delicate interaction of scientific research with societal decisions these processes must proceed in a structured and functional way. We thus propose HES-based TD processes to provide a basis for reorganizing science in coming decades. 相似文献
280.
Susan Taylor David B. Ringelberg Katerina Dontsova Charles P. Daghlian Marianne E. Walsh Michael R. Walsh 《Chemosphere》2013
Two compounds, 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO) are the main ingredients in a suite of explosive formulations that are being, or soon will be, fielded at military training ranges. We aim to understand the dissolution characteristics of DNAN and NTO and three insensitive muntions (IM) formulations that contain them. This information is needed to accurately predict the environmental fate of IM constituents, some of which may be toxic to people and the environment. We used Raman spectroscopy to identify the different constituents in the IM formulations and micro computed tomography to image their three-dimensional structure. These are the first three-dimensional images of detonated explosive particles. 相似文献