全文获取类型
收费全文 | 201篇 |
免费 | 4篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 8篇 |
环保管理 | 123篇 |
综合类 | 30篇 |
基础理论 | 18篇 |
污染及防治 | 10篇 |
评价与监测 | 12篇 |
社会与环境 | 8篇 |
灾害及防治 | 3篇 |
出版年
2022年 | 5篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 1篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 10篇 |
2008年 | 9篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 11篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有212条查询结果,搜索用时 203 毫秒
151.
Jürgen Meyerhoff Alexandra Dehnhardt Volkmar Hartje 《Journal of Environmental Planning and Management》2010,53(1):107-124
Many inhabitants of Berlin enjoy bathing in lakes and rivers during the summer. However, so far no data exist about who goes bathing and what quality bathers expect from bathing sites. In an online survey conducted during the summer of 2007 respondents were presented with a choice experiment concerning various attributes of bathing sites such as water quality or cleanliness of the beach. Applying both random parameter logit models as well as a latent class model reveals that unobserved taste heterogeneity is present among bathers, i.e. not all bathers would benefit equally from improving bathing sites. A test concerning preference consistency reveals high internal validity. 相似文献
152.
舟山普陀旅游金三角游憩价值评估 总被引:2,自引:0,他引:2
旅行费用法(Travel Cost Method,TCM)是相对成熟的游憩价值评价方法。运用旅行费用法的两种模型--分区旅行费用法(Zonal Travel Cost Method,ZTCM)和旅行费用区间分析法(Travel Cost Interval Analysis,TCIA),以2008年为评价基准年份,以实地调研、问卷调查和访谈等获得的数据为基础,对舟山普陀旅游金三角的游憩价值进行了评估。结果表明:(1)ZTCM评估普陀旅游金三角游憩价值为6396×108元/a,其中直接旅行费用为5071×108元/a,消费者剩余为1325×108元/a;(2)TCIA评估普陀旅游金三角游憩价值为6124×108元/a,其中直接旅行费用为5051×108元/a,消费者剩余为1071×108元/a;(3)ZTCM和TCIA结果的差异主要是消费者剩余的差异。研究提出用两种方法结果的均值作为游憩价值能提高评估结果的准确性 相似文献
153.
A study was begun in the winter of 2000–2001 and continued through the winter of 2001–2002 to examine air quality at the Green
Rock snowmobile staging area at 2,985 m elevation in the Snowy Range of Wyoming. The study was designed to evaluate the effects
of winter recreation snowmobile activity on air quality at this high elevation site by measuring levels of nitrogen oxides
(NO
x
, NO), carbon monoxide (CO), ozone (O3) and particulate matter (PM10 mass). Snowmobile numbers were higher weekends than weekdays, but numbers were difficult to quantify with an infrared sensor.
Nitrogen oxides and carbon monoxide were significantly higher weekends than weekdays. Ozone and particulate matter were not
significantly different during the weekend compared to weekdays. Air quality data during the summer was also compared to the
winter data. Carbon monoxide levels at the site were significantly higher during the winter than during the summer. Nitrogen
oxides and particulates were significantly higher during the summer compared to winter. Nevertheless, air pollutants were
well dispersed and diluted by strong winds common at the site, and it appears that snowmobile emissions did not have a significant
impact on air quality at this high elevation ecosystem. Pollutant concentrations were generally low both winter and summer.
In a separate study, water chemistry and snow density were measured from snow samples collected on and adjacent to a snowmobile
trail. Snow on the trail was significantly denser and significantly more acidic with significantly higher concentrations of
sodium, ammonium, calcium, magnesium, fluoride, and sulfate than in snow off the trail. Snowmobile activity had no effect
on nitrate levels in snow. 相似文献
154.
Unmanaged recreation presents a challenge to both researchers and managers of outdoor recreation in the United States because
it is shrouded in uncertainty resulting from disagreement over the definition of the problem, the strategies for resolving
the problem, and the outcomes of management. Incomplete knowledge about recreation visitors’ values and relationships with
one another, other stakeholders, and the land further complicate the problem. Uncertainty and social complexity make the unmanaged
recreation issue a wicked problem. We describe the wickedness inherent in unmanaged recreation and some of the implications
of wickedness for addressing the problem for the Front Range of the Rocky Mountains in Colorado. Conclusions about the nature
of the problem are based on a problem appraisal that included a literature review and interviews of key informants. Addressing
wickedness calls for institutional changes that allow for and reward the use of trust building, inclusive communication, and
genuinely collaborative processes. 相似文献
155.
Lu Liu Xinfeng Wang Jianmin Chen Likun Xue Wenxing Wang Liang Wen Dandan Li Tianshu Chen 《环境科学学报(英文版)》2018,30(9):249-260
Peroxyacetyl nitrate(PAN), as a major secondary pollutant, has gained increasing worldwide attentions, but relevant studies in China are still quite limited. During winter of 2015 to summer of 2016, the ambient levels of PAN were measured continuously by an automatic gas chromatograph equipped with an electron capture detector(GC–ECD) analyzer at an urban site in Jinan(China), with related parameters including concentrations of O3, NO, NO_2, PM_(2.5), HONO,the photolysis rate constant of NO_2 and meteorological factors observed concurrently. The mean and maximum values of PAN concentration were(1.89 ± 1.42) and 9.61 ppbv respectively in winter, and(2.54 ± 1.44) and 13.47 ppbv respectively in summer. Unusually high levels of PAN were observed during severe haze episodes in winter, and the formation mechanisms of them were emphatically discussed. Study showed that high levels of PAN in winter were mainly caused by local accumulation and strong photochemical reactions during haze episodes, while mass transport played only a minor role. Accelerated photochemical reactions(compared to winter days without haze) during haze episodes were deduced by the higher concentrations but shorter lifetimes of PAN, which was further supported by the sufficient solar radiation in the photolysis band along with the high concentrations of precursors(NO_2, VOCs) and HONO during haze episodes. In addition, significant PAN accumulation during calm weather of haze episodes was verified by meteorological data. 相似文献
156.
Riikka Paloniemi Jari Niemelä Niko Soininen Tiina Laatikainen Kati Vierikko Aino Rekola 《Local Environment》2018,23(3):366-377
Environmental justice sheds light on the distributive and procedural aspects of planning and decision-making. We examined the challenges arising from the perspective of environmental justice on multi-level and participatory environmental governance by exploring the governance of aquatic environments in the Helsinki Metropolitan Area. We found three main challenges and potential responses to them. First, even though most of Helsinki’s shoreline is free and/or accessible by road and accordingly used actively by people for recreational purposes, many parts of the shoreline are perceived as inaccessible, reflecting a need to combine factual and perceived accessibility of aquatic environments in detail during the planning processes and to discuss reasons for possible discrepancies between these two. Second, there was a remarkable seasonal variation in the use of aquatic environments, so more attention should be paid to social-demographic factors explaining the distribution of the use of urban nature. Third, it seems to be difficult to capture the variety of perceptions of people and to integrate them into planning and decision-making processes even on a local scale, and this challenge is likely even more pronounced on higher levels of planning and governance. Thus, better integration of regional and local-scale planning procedures should be encouraged. Building on these observations, we conclude that integration of procedural and distributive environmental justice into the practices of the governance of aquatic environments could remarkably decrease unwanted trade-offs and potential conflicts in their use and management. 相似文献
157.
Indirect assessment of economic damages from the Prestige oil spill: consequences for liability and risk prevention 总被引:1,自引:0,他引:1
The social losses arising from the Prestige oil spill exceed the compensation granted under the IOPC (International Oil Pollution Compensation) system, with losses estimated at 15 times more than the applicable limit of compensations. This is far above the level of costs for which those responsible for hydrocarbons spills are liable. The highest market losses correspond to sectors of extraction, elaboration and commercialisation of seafood. However, damages to non-commercial natural resources could constitute an outstanding group of losses for which further primary data are needed: these losses would only be compensable under the current system by means of a refund for cleaning and restoration costs. Results show that, in Europe, the responsibility for oil spills in maritime transport is limited and unclear. The consequence of this is net social losses from recurrent oil spills and internationally accepted incentives for risky strategies in the marine transport of hydrocarbons. 相似文献
158.
Zhang Z Zhan X Yan L Li M Hu J Wei F 《Environmental science and pollution research international》2009,16(1):79-84
Background, aim, and scope Foraging patches can be described as a nested hierarchy of aggregated resources, implying that study of foraging by wild animals
should be directed across different spatial scales. However, almost all previous research on habitat selection by the giant
panda has concentrated upon one scale. In this research, we carried out a field study to understand foraging patch selection
by giant pandas in winter at both microhabitat and feeding site scales and, for the first time, attempted to understand how
long it would stay at the feeding sites before moving on.
Materials and methods The field survey was conducted from November 2002 to March 2003 at Fengtongzhai Nature Reserve (102°48′–103°00′ E, 30°19′–30°47′
N), Baoxing County of Sichuan Province, China, to collect data in both microhabitat and control plots. The microhabitat plots
were located by fresh feces or foraging traces left by giant pandas, and the control plots were established to reflect the
environment. Within each microhabitat plot, one 1 × 1 m2 plot was centralized at the center of each feeding site, in which numbers of old bamboos and old shoots, including eaten
and uneaten, were counted, respectively.
Results The results showed that winter microhabitats selected by this species were characteristic of gentle slopes and high old-shoot
proportions and that the latter was even higher at feeding sites. Two selection processes, namely, from the environment to
microhabitats and from the latter to feeding sites, were found during this species’ foraging patch utilization. Giant pandas
preferred to eat old shoots to old bamboo at feeding sites in winter and did not leave unless old-shoot density fell to lower
than the average in the environment.
Discussion Both microhabitats and feeding sites selected by giant pandas were characteristic of high old-shoot density, indicating that
the preferred food item had a significant influence upon its foraging patch selection. The preference for gentle slopes by
giant pandas was presumed to save energy in movement or reflect the need to sit and free its fore-limbs to grasp bamboo culms
when feeding but also seemed to be correlated with an easier access to old shoots. The utilization of old shoots at feeding
sites was assumed to help maximize energy or nutrient intake during their foraging.
Conclusions The difference between microhabitat plots and control plots and between microhabitats and feeding sites uncovered a continuous
selection process from the environment via microhabitats to feeding sites. The utilization of old shoots at feeding sites
was parallel to the marginal value theorem. The selection and abandonment of foraging patches by giant pandas was an optimal
behavioral strategy adapted to their peculiar food with high cellulose and low protein.
Recommendations and perspectives Our results uncovered the importance of multiple scales in habitat selection research. To further understand the process of
habitat selection, future research should pay more attention to resolve the question of how to locate foraging patches under
dense bamboo forests by the giant panda, which was traditionally considered to have poor eyesight, although our research has
answered what type of habitats the giant panda prefers and when to leave. 相似文献
159.
Assessing current and future ozone-induced yield reductions for rice and winter wheat in Chongqing and the Yangtze River Delta of China 总被引:1,自引:0,他引:1
Dose-response functions from China were employed to assess ozone (O3)-induced relative yield loss (RYL) for rice and winter wheat in Chongqing and the Yangtze River Delta (YRD) in 1990-2020, based on monitored and simulated O3 exposures. It shows that RYL for rice in Chongqing from 1990 to 1995 was 1.1-5.8% and would reach 10.8% in 2020, while for winter wheat it was estimated to be 0.2-9.8% in 1990 and would reach around 12.0% in 2020. In the YRD, RYL for rice was 2.5-6.6% from 1990 to 1999 and would reach 9.2% in 2020, while for winter wheat, RYL was estimated to be 7.1-8.4% based on simulated O3 dosages, while based on monitored O3 dosages, it had surpassed 8.4% and reached about 12.0% in 1999. 相似文献
160.
The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain 总被引:7,自引:0,他引:7
Zhou SL Wu YC Wang ZM Lu LQ Wang RZ 《Environmental pollution (Barking, Essex : 1987)》2008,152(3):723-730
In winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain, maize roots do not extend beyond 1.2 m in the vertical soil profile, but wheat roots can reach up to 2.0 m. Increases in soil nitrate content at maize harvest and significant reductions after winter wheat harvest were observed in the 1.4-2.0 m depth under field conditions. The recovery of 15N isotope (calcium nitrate) from various (1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 m) soil depths showed that deep-rooting winter wheat could use soil nitrate up to the 2.0 m depth. This accounted partially, for the reduced nitrate in the 1.4-2.0 m depth of the soil after harvest of wheat in the rotation system. 相似文献