全文获取类型
收费全文 | 3653篇 |
免费 | 68篇 |
国内免费 | 40篇 |
专业分类
安全科学 | 175篇 |
废物处理 | 144篇 |
环保管理 | 685篇 |
综合类 | 601篇 |
基础理论 | 831篇 |
环境理论 | 3篇 |
污染及防治 | 879篇 |
评价与监测 | 218篇 |
社会与环境 | 180篇 |
灾害及防治 | 45篇 |
出版年
2023年 | 32篇 |
2022年 | 40篇 |
2021年 | 50篇 |
2020年 | 47篇 |
2019年 | 47篇 |
2018年 | 93篇 |
2017年 | 110篇 |
2016年 | 126篇 |
2015年 | 135篇 |
2014年 | 135篇 |
2013年 | 213篇 |
2012年 | 165篇 |
2011年 | 266篇 |
2010年 | 197篇 |
2009年 | 185篇 |
2008年 | 202篇 |
2007年 | 215篇 |
2006年 | 198篇 |
2005年 | 125篇 |
2004年 | 151篇 |
2003年 | 115篇 |
2002年 | 119篇 |
2001年 | 107篇 |
2000年 | 58篇 |
1999年 | 46篇 |
1998年 | 44篇 |
1997年 | 40篇 |
1996年 | 44篇 |
1995年 | 47篇 |
1994年 | 38篇 |
1993年 | 23篇 |
1992年 | 31篇 |
1991年 | 33篇 |
1990年 | 22篇 |
1989年 | 23篇 |
1988年 | 17篇 |
1987年 | 19篇 |
1986年 | 11篇 |
1985年 | 10篇 |
1984年 | 14篇 |
1983年 | 9篇 |
1982年 | 20篇 |
1981年 | 14篇 |
1980年 | 8篇 |
1979年 | 15篇 |
1970年 | 7篇 |
1969年 | 7篇 |
1967年 | 5篇 |
1965年 | 5篇 |
1960年 | 4篇 |
排序方式: 共有3761条查询结果,搜索用时 874 毫秒
151.
Kinetic extractions to assess mobilization of Zn, Pb, Cu, and Cd in a metal-contaminated soil: EDTA vs. citrate 总被引:4,自引:0,他引:4
Labanowski J Monna F Bermond A Cambier P Fernandez C Lamy I van Oort F 《Environmental pollution (Barking, Essex : 1987)》2008,152(3):693-701
Kinetic EDTA and citrate extractions were used to mimic metal mobilization in a soil contaminated by metallurgical fallout. Modeling of metal removal rates vs. time distinguished two metal pools: readily labile (QM1) and less labile (QM2). In citrate extractions, total extractability (QM1+QM2) of Zn and Cd was proportionally higher than for Pb and Cu. Proportions of Pb and Cu extracted with EDTA were three times higher than when using citrate. We observed similar QM1/QM2 ratios for Zn and Cu regardless of the extractant, suggesting comparable binding energies to soil constituents. However, for Pb and Cd, more heterogeneous binding energies were hypothesized to explain different kinetic extraction behaviors. Proportions of citrate-labile metals were found consistent with their short-term, in-situ mobility assessed in the studied soil, i.e., metal amount released in the soil solution or extracted by cultivated plants. Kinetic EDTA extractions were hypothesized to be more predictive for long-term metal migration with depth. 相似文献
152.
Paumen ML Borgman E Kraak MH van Gestel CA Admiraal W 《Environmental pollution (Barking, Essex : 1987)》2008,152(1):225-232
During acute exposure, polycyclic aromatic compounds (PACs) act mainly by narcosis, but during chronic exposure the same compounds may exert sublethal life cycle effects. The aim of this study was therefore to evaluate the chronic effects of sediment spiked PACs on the emergence of the midge Chironomus riparius. Three isomer pairs were selected, and 28-day LC50 values and 50% emergence times (EMt50) were determined. Concentration-response relationships were observed for phenanthrene, acridine, phenanthridine and acridone. Anthracene and phenanthridone had no effect on total emergence, but did cause a delay in emergence. Calculated porewater LC50 values correlated well with logKow values, suggesting narcosis as mode of action. In contrast, effect concentrations for delay in emergence (EMt50) deviated from narcosis, suggesting a specific mode of action during chronic exposure. It is concluded that emergence is a powerful endpoint to detect life cycle effects of PACs on a key sediment inhabiting invertebrate. 相似文献
153.
Margaret Lumia Charles A. Gentile Philip Efthimion Mark Gregory Robson 《补救:环境净化治理成本、技术与工艺杂志》2008,18(2):115-130
This article summarizes a study that evaluated a new decontamination technique for the mitigation and abatement of hazardous dust and particulates. Traditional decontamination methods are time‐consuming, expensive, can create airborne hazards, and do not always bring the concentration of the contaminant to acceptable levels. The use of the removable thin film coating will increase efficiency, will not generate airborne hazards, will decrease costs, and, with one application, will bring the hazardous dust concentrations to acceptable levels. Qualitative tests demonstrated that the removable thin film coating reduced the amount of visible luminescent dust (a surrogate for hazardous dust) from various surfaces. It also indicated that wherever there were minute scratches, the coating did not remove all of the dust. However, the qualitative tests showed that this decontamination method worked well as a preventative method, protecting clean areas from becoming contaminated when exposed to the luminescent dust. Further investigation was conducted using a scanning electron microscope (SEM) and carbon dust. Overall, the SEM experiment demonstrated that there was a statistically significant (p = 0.00007) removal of carbon dust (less than 10 μm in size) from surfaces with crevasses larger than 3 μm. The SEM also revealed that there were some limitations where there were large clusters of carbon dust; in these instances, the coating would tear and remain on the sample surface. One method to resolve this limitation involved adding KevlarTM fibers to the removable thin film coating. It was thought that this would increase the strength of the coating and eliminate the coating from tearing when removing large clusters of a contaminant. Unfortunately, this did not alleviate the issue. The use of an engineered textile, saturated with the coating, appeared to eliminate the problem with the coating not being able to remove the contaminant from the minute surface scratches and improved the removal process of the coating. © 2008 Wiley Periodicals, Inc. 相似文献
154.
The provision of green space is increasingly being perceived as an important factor for quality of life. However, green spaces often face high developmental pressure. The main objective of this study is to investigate a prospective approach to green space planning by combining three-dimensional (3D) visualization of green space scenarios and survey techniques to facilitate improved participation of the public. Aside from the ‘Status quo’, scenarios ‘Agriculture’, ‘Recreation’, ‘Nature conservation’ and ‘Wind turbines’ are visualized in three dimensions. In order to test responses, a survey was conducted both in print format and on the Internet. Overall, 49 different visualizations that belong to one of the scenarios were available in the survey and were rated according to the perceived esthetic, recreational and ecological values.The highest rated scenes include vegetation elements such as meadows with orchards, single trees, shrubs or forest. The least attractive scenes are those where buildings are highly dominant or where there are no vegetation elements.Based on the ratings for the individual images and on the corresponding scenarios, our study shows that there is high potential for improving the existing landscape. All suggested changes are either rated about equal to or considerably higher than the status quo, with the scenario ‘Nature conservation’ receiving the highest scores. 相似文献
155.
In areas of war and armed conflict it is difficult to get trustworthy and coherent information. Civil society and human rights groups often face problems of dealing with fragmented witness reports, disinformation of war propaganda, and difficult direct access to these areas. Turkish Kurdistan was used as a case study of armed conflict to evaluate the potential use of satellite images for verification of witness reports collected by human rights groups. The Turkish army was reported to be burning forests, fields and villages as a strategy in the conflict against guerrilla uprising. This paper concludes that satellite images are useful to validate witness reports of forest fires. Even though the use of this technology for human rights groups will depend on some feasibility factors such as prices, access and expertise, the images proved to be key for analysis of spatial aspects of conflict and valuable for reconstructing a more trustworthy picture. 相似文献
156.
Mark Duffield 《Disasters》2001,25(4):308-320
This article examines aid practice, that is, the public-private contractual networks that link donor governments, UN agencies, military establishments, NGOs, private companies and others, as a relation of global liberal governance. In order to fulfil this function, such networks embody what could be called the 'securitisation' of international assistance. Based upon ideas of human security and ameliorating the effects of poverty and vulnerability reduction, aid is now seen as playing a direct security role. Rather than being concerned with relations between states, the primary aim of this security paradigm is to modulate and change the behaviour of populations within them. In doing so, it is able to exploit the opportunities afforded by privatisation. At the same time, however, aid as security is confronted by its own particular problem of 'governing at a distance'; how can calculations made by leading states be transformed into actions at the global edge when a multitude of private and non-government implementors now intervene? The article concludes by examining the contribution of risk analysis to solving this problem and, especially, the development of new contractual regimes based around technical standardisation, benchmarking and performance auditing. Through such technologies, metropolitan states are learning how to manage the public-private networks of aid practice and, as a result, to govern the borderlands in new ways. 相似文献
157.
158.
Summary. Chemical defense against herbivores has rarely been investigated for freshwater plants, possibly due to the common misconception
that herbivory on aquatic macrophytes is low and would not select for chemical defenses. In previous work, the freshwater
angiosperm Saururus cernuus was shown to be a low preference food for omnivorous crayfish despite its high nutrient value and relatively soft texture.
We used feeding by the crayfish Procambarus clarkii to guide fractionation of the deterrent lipid-soluble extract of this plant, leading to the identification of seven deterrent
lignoid metabolites, (–)-licarin A, (+)-saucernetin, (–)-dihydroguaiaretic acid, (–)-sauriols A and B, (–)-saucerneol, and
(–)-saucerneol methyl ether. Lignans have been implicated in terrestrial plant chemical defenses as insect growth inhibitors,
insect toxins, nematocides, antibacterial, and antifungal agents. However, these activities have rarely been demonstrated
using ecologically relevant methodologies in terrestrial systems, and never before in freshwater systems. The widespread nature
of lignans amongst very distantly related plants, along with their rich diversity of molecular structure, suggests that they
could play a large role in mediating plant-herbivore interactions. In addition to the lignoid compounds we identified, there
were other compounds present in low concentration or unstable compounds that were deterrent, that did not appear to be lignans,
but that we were unable to identify. This plant thus appears to be defended by a complex mixture of natural products.
Received 6 June 2000; revised 23 August 2000; accepted 2 September 2000 相似文献
159.
Claudia Voelckel Tamara Krügel Klaus Gase Nadja Heidrich Nicole M. van Dam Robert Winz Ian T. Baldwin 《Chemoecology》2001,11(3):121-126
160.
Synergistic Interactions between Habitat Fragmentation and Fire in Evergreen Tropical Forests 总被引:5,自引:0,他引:5
Mark A. Cochrane 《Conservation biology》2001,15(6):1515-1521
Abstract: The growing prevalence of fragmentation and fire in tropical forests makes it imperative to quantify changes in these disturbances and to understand the ways in which they interact across the landscape. I used a multitemporal series of Landsat images to study the incidence and coincidence of fire and fragmentation in two areas of Pará state in the eastern Brazilian Amazon: Tailândia and Paragominase. In both areas, deforestation and forest fires were quantified for time series of 6–10 years. The Tailândia study area typifies a landscape with the herringbone pattern of government-settled colonists, and the Paragominas area is dominated by large cattle ranches. In both areas, over 90% of the forests affected by fire were associated with forest edges. Although most burned forest occurred within 500 m of forest edges, some fires occurred in deep forest, several kilometers from any edge. The obvious synergism between forest fragmentation and fire poses serious risks to tropical ecosystems and has important implications for land management. 相似文献