全文获取类型
收费全文 | 5889篇 |
免费 | 43篇 |
国内免费 | 22篇 |
专业分类
安全科学 | 137篇 |
废物处理 | 223篇 |
环保管理 | 339篇 |
综合类 | 1755篇 |
基础理论 | 1319篇 |
环境理论 | 9篇 |
污染及防治 | 1547篇 |
评价与监测 | 326篇 |
社会与环境 | 289篇 |
灾害及防治 | 10篇 |
出版年
2022年 | 65篇 |
2021年 | 64篇 |
2020年 | 47篇 |
2019年 | 59篇 |
2018年 | 177篇 |
2017年 | 171篇 |
2016年 | 204篇 |
2015年 | 149篇 |
2014年 | 186篇 |
2013年 | 311篇 |
2012年 | 202篇 |
2011年 | 320篇 |
2010年 | 208篇 |
2009年 | 203篇 |
2008年 | 311篇 |
2007年 | 265篇 |
2006年 | 229篇 |
2005年 | 180篇 |
2004年 | 164篇 |
2003年 | 142篇 |
2002年 | 168篇 |
2001年 | 106篇 |
2000年 | 88篇 |
1999年 | 66篇 |
1998年 | 47篇 |
1997年 | 43篇 |
1996年 | 54篇 |
1995年 | 56篇 |
1994年 | 54篇 |
1993年 | 40篇 |
1992年 | 48篇 |
1991年 | 46篇 |
1990年 | 40篇 |
1989年 | 35篇 |
1988年 | 34篇 |
1981年 | 34篇 |
1976年 | 35篇 |
1967年 | 34篇 |
1966年 | 33篇 |
1965年 | 49篇 |
1964年 | 41篇 |
1963年 | 38篇 |
1961年 | 46篇 |
1960年 | 41篇 |
1959年 | 43篇 |
1958年 | 46篇 |
1957年 | 40篇 |
1956年 | 40篇 |
1955年 | 38篇 |
1954年 | 42篇 |
排序方式: 共有5954条查询结果,搜索用时 281 毫秒
571.
Carolyn Fischer Asbjrn Torvanger Manish Kumar Shrivastava Thomas Sterner Peter Stigson 《Ambio》2012,41(1):33-45
Stabilizing global greenhouse gas concentrations at levels to avoid significant climate risks will require massive “decarbonization” of all the major economies over the next few decades, in addition to the reduced emissions from other GHGs and carbon sequestration. Achieving the necessary scale of emissions reductions will require a multifaceted policy effort to support a broad array of technological and behavioral changes. Change on this scale will require sound, well-thought-out strategies. In this article, we outline some core principles, drawn from recent social science research, for guiding the design of clean technology policies, with a focus on energy. The market should be encouraged to make good choices: pricing carbon emissions and other environmental damage, removing distorting subsidies and barriers to competition, and supporting RD&D broadly. More specific policies are required to address particular market failures and barriers. For those technologies identified as being particularly desirable, some narrower RD&D policies are available. 相似文献
572.
Mechanical biological treatment (MBT) of municipal solid waste (MSW) has become an important technology in waste management during the last decade. The paper compiles investigations of mechanical biological processes in Austrian MBT plants. Samples from all plants representing different stages of degradation were included in this study. The range of the relevant parameters characterizing the materials and their behavior, e.g. total organic carbon, total nitrogen, respiration activity and gas generation sum, was determined. The evolution of total carbon and nitrogen containing compounds was compared and related to process operation. The respiration activity decreases in most of the plants by about 90% of the initial values whereas the ammonium release is still ongoing at the end of the biological treatment. If the biogenic waste fraction is not separated, it favors humification in MBT materials that is not observed to such extent in MSW. The amount of organic carbon is about 15% dry matter at the end of the biological treatment. 相似文献
573.
574.
Johan Östberg Tim Delshammar Björn Wiström Anders Busse Nielsen 《Environmental management》2013,51(3):694-708
Tree inventories are expensive to conduct and update, so every inventory carried out must be maximized. However, increasing the number of constituent parameters increases the cost of performing and updating the inventory, illustrating the need for careful parameter selection. This article reports the results of a systematic expert rating of tree inventories aiming to quantify the relative importance of each parameter. Using the Delphi method, panels comprising city officials, arborists, and academics rated a total of 148 parameters. The total mean score, the top ranking parameters, which can serve as a guide for decision-making at practical level and for standardization of tree inventories, were: Scientific name of the tree species and genera, Vitality, Coordinates, Hazard class, and Identification number. The study also examined whether the different responsibilities and usage of urban tree databases among organizations and people engaged in urban tree inventories affected their prioritization. The results revealed noticeable dissimilarities in the ranking of parameters between the panels, underlining the need for collaboration between the research community and those commissioning, administrating, and conducting inventories. Only by applying such a transdisciplinary approach to parameter selection can urban tree inventories be strengthened and made more relevant. 相似文献
575.
Marcela Rodrigues De Camargo Luís Fernando Barbisan Meire França Martinez Carla Adriene Da Silva Franchi João Lauro Viana De Camargo Ana Lúcia Tozzi Spinardi-Barbisan 《Journal of environmental science and health. Part. B》2013,48(7):607-613
The noxious effects of low or effective dose exposure to single or mixed pesticides on macrophage activity and the lymphohematopoietic organs were investigated. Male Wistar rats were orally exposed to dichlorvos, dicofol, endosulfan, dieldrin and permethrin, either as single or combined mixtures during a 28-day study containing eight groups: one group received a semipurified diet (non-treated); two groups received a semipurified diet containing low dose mixture (dieldrin 0.025 mg/kg, endosulfan, 0.6 mg/kg, dicofol 0.22 mg/kg, dichlorvos 0.23 mg/kg, permethrin 5 mg/kg) or an effective dose mixture (dichlorvos 2.3 mg/kg, dicofol 2.5 mg/kg, endosulfan 2.9 mg/kg, dieldrin 0.05 mg/kg and permethrin 25.0 mg/kg), respectively; the other five groups received a semipurified diet containing each single pesticide in effective doses. At sacrifice, the thymus, spleen, mesenteric lymph nodes, Payer's patches and bone marrow were removed for histological analysis. Peritoneal macrophages were obtained to determine the phagocytosis and spreading indexes and tumoral necrosis factor alpha (TNF-α), nitric oxide (NO) and H2O2 production. Exposure to pesticide mixtures did not alter the percentage of macrophage phagocytosis and spreading, TNF-α production or the NO and H2O2 release when compared to the non-treated group. Neither was there any apparent evidence that a pesticide mixture at low or effective doses altered the histological structure of the lymphohematopoietic organs. The findings indicate that short-term treatment with pesticide mixtures did not induce an apparent immunotoxic effect in male Wistar rats. 相似文献
576.
Jeffrey H. R. Goddard Maria C. Schaefer Craig Hoover Ángel Valdés 《Marine Biology》2013,160(6):1497-1510
Felimare californiensis (=Hypselodoris californiensis) was once common throughout the Southern California Bight (SCB) and California Channel Islands. This well-known shallow-water nudibranch, which specializes on dysideid sponges, has persisted for decades in Mexico, but in California disappeared from its entire range by 1984. Since reappearing in 2003, it has been found only at Santa Catalina Island, plus sightings of single individuals in 2011 at Santa Cruz Island and San Diego. The decline of F. californiensis in California was documented using published historical records, museum collections, unpublished field accounts, and images posted online. The loss of this emblematic species is unique among Californian nudibranchs, including (1) its congener Felimare porterae (=Mexichromis porterae), with which it appears to overlap in diet, and (2) opisthobranch species with similar historical geographic ranges and mode of development. The decline in F. californiensis is not predicted by warming trends and climate variation over the past 40 years, including the strong El Niño events of 1983 and 1998. Coastal pollution from the large human population in southern California may have impacted Dysidea amblia, the primary reported prey of F. californiensis. Historical overcollecting of the nudibranch and habitat loss through the development of major ports likely also contributed to its decline. Sightings since 2003 are consistent with a nascent recovery, as elements of water quality have improved in the SCB in recent decades. 相似文献
577.
578.
Claudia S. Hak Mattias Hallquist Evert Ljungström Maria Svane Jan B.C. Pettersson 《Atmospheric environment (Oxford, England : 1994)》2009,43(15):2481-2488
A method for continuous on-road measurements of particle number emissions for both diesel- and petrol-fuelled vehicles is presented. The setup allows the determination of particle number emission factors on an individual vehicle basis by the simultaneous measurement of CO2 and particle concentrations. As an alternative to previous measurements on the kerbside, the sample is taken directly in the street, with the advantage of sampling in-situ within the exhaust plumes of passing vehicles, allowing the separation of the individual high-concentration plumes. The method was tested in two experiments that were conducted in the Gothenburg area. In the first study, which was performed at an urban roadside, we were able to determine particle emission factors from individual vehicles in a common car fleet passing the measurement site. The obtained emission factors were of the same order of magnitude (between 1.4 × 1012 and 1.8 × 1014 particles km?1) as values published in the recent literature for light duty vehicles. An additional on-road experiment was conducted at a rural road with four light duty reference vehicles (three of them petrol-powered and one diesel-powered) at driving speeds of 50 and 70 km h?1, realised with different engine speeds. The results of the traffic emission studies show that the method is applicable provided that instruments with an adequate dynamic range are used and that the traffic is not too dense. In addition, the variability in particle emissions for a specified driving condition was estimated. 相似文献
579.
580.
Regina Lindborg Marie Stenseke Sara A.O. Cousins Jan Bengtsson Åke Berg Tomas Gustafsson N. Erik Sjödin Ove Eriksson 《Journal of environmental management》2009,90(2):499-508
Agriculture is the major land use at a global scale. In addition to food production, multifunctionality of landscapes, including values and ecosystem services like biodiversity, recreation and culture, is now focus for management. This study explores how a scenario approach, involving different stakeholders, may help to improve landscape management for biodiversity conservation. Local farmers and executives at the County Administrative Board were invited to discuss rural development and conditions for farmland biodiversity in two Swedish landscapes. The potential biodiversity for three future land use scenarios for the two landscapes was discussed: nature conservation, outdoor recreation and energy production, and compared with current and historical landscapes in each region.Analyses of habitat areas, connectedness and landscape diversity suggested that the energy and recreation scenarios had a negative impact on farmland biodiversity, whereas the nature conservation scenario, the current and historically reconstructed landscapes had a higher potential for biodiversity. The farmers appreciated the nature conservation scenario, but also the energy production scenario and they highlighted the need of increased subsidies for management of biodiversity. The farmers in the high production area were less interested in nature quality per se. The executives had similar opinions as the farmers, but disagreed on the advantages with energy production, as this would be in conflict with the high biodiversity and recreational values. The local physical and socio-economical conditions differ between landscapes and potentially shaped the stakeholders emotional attachment to the local environment, their opinions and decisions on how to manage the land. We stress the importance of incorporating local knowledge, visions and regional prerequisites for different land uses in conservation, since site and landscape specific planning for biodiversity together with a flexible subsidy system are necessary to reach the conservation goals within EU. 相似文献