全文获取类型
收费全文 | 9838篇 |
免费 | 113篇 |
国内免费 | 93篇 |
专业分类
安全科学 | 283篇 |
废物处理 | 461篇 |
环保管理 | 1243篇 |
综合类 | 1194篇 |
基础理论 | 2667篇 |
环境理论 | 2篇 |
污染及防治 | 2771篇 |
评价与监测 | 708篇 |
社会与环境 | 667篇 |
灾害及防治 | 48篇 |
出版年
2022年 | 100篇 |
2021年 | 76篇 |
2020年 | 65篇 |
2019年 | 72篇 |
2018年 | 145篇 |
2017年 | 139篇 |
2016年 | 229篇 |
2015年 | 164篇 |
2014年 | 237篇 |
2013年 | 742篇 |
2012年 | 296篇 |
2011年 | 440篇 |
2010年 | 362篇 |
2009年 | 395篇 |
2008年 | 470篇 |
2007年 | 475篇 |
2006年 | 422篇 |
2005年 | 366篇 |
2004年 | 323篇 |
2003年 | 375篇 |
2002年 | 324篇 |
2001年 | 506篇 |
2000年 | 331篇 |
1999年 | 192篇 |
1998年 | 137篇 |
1997年 | 133篇 |
1996年 | 138篇 |
1995年 | 162篇 |
1994年 | 125篇 |
1993年 | 102篇 |
1992年 | 123篇 |
1991年 | 118篇 |
1990年 | 130篇 |
1989年 | 130篇 |
1988年 | 94篇 |
1987年 | 87篇 |
1986年 | 65篇 |
1985年 | 90篇 |
1984年 | 89篇 |
1983年 | 86篇 |
1982年 | 82篇 |
1981年 | 73篇 |
1980年 | 61篇 |
1979年 | 68篇 |
1977年 | 53篇 |
1976年 | 48篇 |
1975年 | 53篇 |
1974年 | 51篇 |
1973年 | 53篇 |
1970年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Stuart W. Krasner Ai Ji Chih-Fen T. Lee Raha Shirkhani Joshua M. Allen Susan D. Richardson Michael J. Plewa 《环境科学学报(英文版)》2022,34(7):161-172
A survey was conducted at eight U.S. drinking water plants, that spanned a wide range of water qualities and treatment/disinfection practices. Plants that treated heavily-wastewater-impacted source waters had lower trihalomethane to dihaloacetonitrile ratios due to the presence of more organic nitrogen and HAN precursors. As the bromide to total organic carbon ratio increased, there was more bromine incorporation into DBPs. This has been shown in other studies for THMs and selected emerging DBPs (HANs), whereas this study examined bromine incorporation for a wider group of emerging DBPs (haloacetaldehydes, halonitromethanes). Moreover, bromine incorporation into the emerging DBPs was, in general, similar to that of the THMs. Epidemiology studies that show an association between adverse health effects and brominated THMs may be due to the formation of brominated emerging DBPs of heath concern. Plants with higher free chlorine contact times before ammonia addition to form chloramines had less iodinated DBP formation in chloraminated distribution systems, where there was more oxidation of the iodide to iodate (a sink for the iodide) by the chlorine. This has been shown in many bench-scale studies (primarily for iodinated THMs), but seldom in full-scale studies (where this study also showed the impact on total organic iodine. Collectively, the THMs, haloacetic acids, and emerging DBPs accounted for a significant portion of the TOCl, TOBr, and TOI; however, ∼50% of the TOCl and TOBr is still unknown. The correlation of the sum of detected DBPs with the TOCl and TOBr suggests that they can be used as reliable surrogates. 相似文献
992.
Pöllänen R Ikäheimonen TK Klemola S Vartti VP Vesterbacka K Ristonmaa S Honkamaa T Sipilä P Jokelainen I Kosunen A Zilliacus R Kettunen M Hokkanen M 《Journal of environmental radioactivity》2003,64(2-3):133-142
Projectiles suspected to be composed of depleted uranium (DU) were found in Kosovo. Their properties were analysed using alpha and gamma ray spectrometry, mass spectrometry and electron microscopy. They were found to be composed of DU with small amounts of other elements such as Ti. 236U was detected in the penetrators, reflecting the use of reprocessed fuel. No transuranium elements were detected. The typical external dose rate meter is not the best option for mapping the location of penetrators from the ground. Monte Carlo calculations were performed in estimating possible skin doses. Penetrators in long-lasting contact with skin may cause a notable equivalent dose to skin. 相似文献
993.
Atmospheric xenon radioactive isotope monitoring 总被引:2,自引:0,他引:2
Fontaine JP Pointurier F Blanchard X Taffary T 《Journal of environmental radioactivity》2004,72(1-2):129-135
The Comprehensive Nuclear Test Ban Treaty (CTBT) organisation is implementing a world-wide monitoring network in order to check that the State Signatories comply with the treaty. One of the monitoring facilities consists of an atmospheric noble gas monitoring equipment. According to the requirements annexed in the treaty, the French Atomic Energy Commission (CEA) developed a device, called SPALAX, which automatically extracts xenon from ambient air and makes in situ measurements of the activities of four xenon radioisotopes (131mXe, 133mXe, 133Xe, 135Xe). The originality of this device is noticeable essentially in the gas sample processing method: thanks to the coupling of a gas permeator and of a noble gas specific adsorbent, it can selectively extract and concentrate xenon to more than 3 x 10 E6. This process is carried out continuously without cryogenic cooling, without any regeneration time. The detection of the xenon radioactive isotopes is done automatically by high spectral resolution gamma spectrometry, a robust technology well-suited for on-field instrumentation. In the year 2000, a prototype was involved in an international evaluation exercise directed by the CTBT organisation (CTBTO). This exercise demonstrated that the SPALAX equipment perfectly met the requirements of the CTBTO for such systems. On the basis of the continuous 24-h resolution record of the atmospheric xenon radioactive isotopes concentrations, the SPALAX system also demonstrated that ambient levels of 133Xe can fluctuate quickly from less than the detection limit to over 40 x 10(-3) Bq m(-3). In order to build an industrial version of this equipment, the CEA entered into a partnership with a French engineering company (S.F.I., Marseille, France), which is now able to produce an industrial version of SPALAX, i.e. more compact and more efficient than the prototypes. The 133Xe minimum detectable concentration is 0.15 x 10(-3) Bq m(-3) air per 24 h sampling cycle. 相似文献
994.
995.
Rebecca J. McLain Patrick T. Hurley Marla R. Emery Melissa R. Poe 《Local Environment》2014,19(2):220-240
Recent “green” planning initiatives envision food production, including urban agriculture and livestock production, as desirable elements of sustainable cities. We use an integrated urban political ecology and human–plant geographies framework to explore how foraging for “wild” foods in cities, a subversive practice that challenges prevailing views about the roles of humans in urban green spaces, has potential to also support sustainability goals. Drawing on research from Baltimore, New York City, Philadelphia, and Seattle, we show that foraging is a vibrant and ongoing practice among diverse urban residents in the USA. At the same time, as reflected in regulations, planning practices, and attitudes of conservation practitioners, it is conceptualised as out of place in urban landscapes and an activity to be discouraged. We discuss how paying attention to urban foraging spaces and practices can strengthen green space planning and summarise opportunities for and challenges associated with including foragers and their concerns. 相似文献
996.
Karen R. Hall Jean Spooner Robert J. Richardson Steve T. Hoyle Douglas J. Frederick 《Journal of the American Water Resources Association》2014,50(3):533-542
Microstegium vimineum is an invasive grass introduced from Asia that has spread throughout riparian areas of the eastern United States threatening native riparian vegetation. Postemergence (POST) herbicides registered for aquatic use were evaluated for control of M. vimineum on two riparian restoration sites in the Piedmont and Upper Coastal Plain of North Carolina. This study found that standard and lower than standard rates of diquat, fluridone, flumioxazin, glyphosate, imazamox, and imazapyr reduced weed stem density and biomass at 6 and 30 weeks after treatment (WAT). Both rates of bispyribac and penoxsulam provided less control of M. vimineum. Visual ratings showed both rates of diquat, flumioxazin, imazamox, and imazapyr controlled 63‐100% of M. vimineum at 6 WAT and 84‐100% at 30 WAT. Fluridone and glyphosate provided slightly less control. Bispyribac and penoxsulam treatments provided less control at 6 and 30 WAT compared to the other treatments. Plots treated with both rates of diquat, flumioxazin, imazamox, and imazapyr were nearly devoid of all vegetation at 30 WAT. Recommendations include POST application of lower than standard rates of diquat, flumioxazin, fluridone, glyphosate, imazamox, and imazapyr on riparian restoration sites infested with M. vimineum. Immediate vegetation management measures including temporary and permanent plant cover should be employed on treated sites where weeds are completely eradicated to prevent erosion. 相似文献
997.
Daniel J. Bain Erin M. Copeland Marion T. Divers Marijke Hecht Kristina G. Hopkins Justin Hynicka Michael Koryak Mary Kostalos Lisa Brown Emily M. Elliott Joseph Fedor Michele Gregorich Brady Porter Brenda Smith Christopher Tracey Margaret Zak 《Journal of the American Water Resources Association》2014,50(6):1608-1621
Urban stream restoration continues to be used as an ecological management tool, despite uncertainty about the long‐term sustainability and resilience of restored systems. Evaluations of restoration success often focus on specific instream indicators, with limited attention to the wider basin or parallel hydrologic and geomorphic process. A comprehensive understanding of urban stream restoration progress is particularly important for comparisons with nonurban sites as urban streams can provide substantial secondary benefits to urban residents. Here, we utilize a wide range of indicators to retrospectively examine the restoration of Nine Mile Run, a multi‐million dollar stream restoration project in eastern Pittsburgh (Pennsylvania, USA). Examination of available continuous hydrological data illustrates the high cost of failures to incorporate the data into planning and adaptive management. For example, persistent extreme flows drive geomorphic degradation threatening to reverse hydrologic connections created by the restoration and impact the improved instream biotic communities. In addition, human activities associated with restoration efforts suggest a positive feedback as the stream restoration has focused effort on the basin beyond the reach. Ultimately, urban stream restoration remains a potentially useful management tool, but continued improvements in post‐project assessment should include examination of a wider range of indicators. 相似文献
998.
A. Basile S. Sorbo G. Aprile B. Conte R. Castaldo Cobianchi T. Pisani S. Loppi 《Environmental pollution (Barking, Essex : 1987)》2009,157(8-9):2255-2260
In this study, a biomonitoring project using the moss Scorpiurum circinatum was carried out to evaluate the deposition and biological effects of heavy metals in the area of Acerra (Naples, S Italy), one of the vertices of the sadly called “Italian triangle of death” owing to the dramatic increase in tumours. The results clearly indicated that the study area is heavily polluted by heavy metals, a large proportion of which is likely present in the atmosphere in particulate form. The ultrastructural organization of exposed samples was essentially preserved, but cell membrane pits, cytoplasm vesicles and concentric multilamellar/multivesicular bodies, probably induced by pollution, were found, which may be involved in the tolerance mechanisms to metal pollution in this moss species. Although severe biological effects were not found at the ultrastructural level in the exposed moss, effects on humans, especially after long-term exposure, are to be expected. 相似文献
999.
HERMAN T. FRANSSEN 《Natural resources forum》1977,1(2):157-165
Evaluation of energy options and adoption of appropriate policies require rigorous demand and supply projections. The wider the options, the more difficult the task. The author reviews the various projections which have been made in the United States to support a policy toward energy independence. He sets the stage for a similar review of the 1977 National Energy Outlook, scheduled for publication early in the year, in a subsequent issue of the Forum. 相似文献
1000.
ANDREW T. KNIGHT RICHARD M. COWLING MARK DIFFORD BRUCE M. CAMPBELL 《Conservation biology》2010,24(5):1348-1358
Abstract Spatial prioritization techniques are applied in conservation‐planning initiatives to allocate conservation resources. Although typically they are based on ecological data (e.g., species, habitats, ecological processes), increasingly they also include nonecological data, mostly on the vulnerability of valued features and economic costs of implementation. Nevertheless, the effectiveness of conservation actions implemented through conservation‐planning initiatives is a function of the human and social dimensions of social‐ecological systems, such as stakeholders’ willingness and capacity to participate. We assessed human and social factors hypothesized to define opportunities for implementing effective conservation action by individual land managers (those responsible for making day‐to‐day decisions on land use) and mapped these to schedule implementation of a private land conservation program. We surveyed 48 land managers who owned 301 land parcels in the Makana Municipality of the Eastern Cape province in South Africa. Psychometric statistical and cluster analyses were applied to the interview data so as to map human and social factors of conservation opportunity across a landscape of regional conservation importance. Four groups of landowners were identified, in rank order, for a phased implementation process. Furthermore, using psychometric statistical techniques, we reduced the number of interview questions from 165 to 45, which is a preliminary step toward developing surrogates for human and social factors that can be developed rapidly and complemented with measures of conservation value, vulnerability, and economic cost to more‐effectively schedule conservation actions. This work provides conservation and land management professionals direction on where and how implementation of local‐scale conservation should be undertaken to ensure it is feasible. 相似文献