全文获取类型
收费全文 | 3305篇 |
免费 | 68篇 |
国内免费 | 33篇 |
专业分类
安全科学 | 114篇 |
废物处理 | 102篇 |
环保管理 | 609篇 |
综合类 | 522篇 |
基础理论 | 868篇 |
环境理论 | 9篇 |
污染及防治 | 794篇 |
评价与监测 | 192篇 |
社会与环境 | 149篇 |
灾害及防治 | 47篇 |
出版年
2023年 | 13篇 |
2022年 | 15篇 |
2021年 | 39篇 |
2020年 | 20篇 |
2019年 | 32篇 |
2018年 | 80篇 |
2017年 | 76篇 |
2016年 | 84篇 |
2015年 | 86篇 |
2014年 | 95篇 |
2013年 | 243篇 |
2012年 | 156篇 |
2011年 | 203篇 |
2010年 | 149篇 |
2009年 | 163篇 |
2008年 | 174篇 |
2007年 | 205篇 |
2006年 | 205篇 |
2005年 | 150篇 |
2004年 | 107篇 |
2003年 | 102篇 |
2002年 | 116篇 |
2001年 | 65篇 |
2000年 | 57篇 |
1999年 | 47篇 |
1998年 | 50篇 |
1997年 | 59篇 |
1996年 | 46篇 |
1995年 | 54篇 |
1994年 | 49篇 |
1993年 | 29篇 |
1992年 | 31篇 |
1991年 | 23篇 |
1990年 | 23篇 |
1989年 | 11篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 19篇 |
1985年 | 17篇 |
1984年 | 19篇 |
1983年 | 21篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 18篇 |
1979年 | 20篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1965年 | 11篇 |
1963年 | 8篇 |
1957年 | 10篇 |
排序方式: 共有3406条查询结果,搜索用时 62 毫秒
31.
Rebecca Spicer Amin Vahabaghaie George Bahouth Ludwig Drees Robert Martinez von Bülow Peter Baur 《Traffic injury prevention》2018,19(8):S91-S95
AbstractObjective: Advanced driver assistance systems (ADAS) are a class of vehicle technologies designed to increase safety by providing drivers with timely warnings and autonomously intervening to avoid hazardous situations. Though laboratory testing suggests that ADAS technologies will greatly impact crash involvement rates, real-world evidence that characterizes their effectiveness is still limited. This study evaluates and quantifies the association of ADAS technologies with the likelihood of a moderate or severe crash for new-model BMWs in the United States.Methods: Vehicle ADAS option information for the cohort of model year 2014 and later BMW passenger vehicles sold after January 1, 2014 (n?=?1,063,503), was coded using VIN-identified options data. ADAS technologies of interest include frontal collision warning with autonomous emergency braking, lane departure warning, and blind spot detection. BMW Automated Crash Notification system data (from January 2014 to November 2017) were merged with vehicle data by VIN to identify crashed vehicles (n?=?15,507), including date, crash severity (delta V), and area of impact. Using Cox proportional hazards regression modeling, the study calculates the adjusted hazard ratio for crashing among BMW passenger vehicles with versus without ADAS technologies. The adjusted percentage reduction in moderate and severe crashes associated with ADAS is interpreted as one minus the hazard ratio.Results: Vehicles equipped with both autonomous emergency braking and lane departure warning were 23% less likely to crash than those not equipped (hazard ratio [HR]?=?0.77; 95% confidence interval [CI], 0.73–0.81), controlling for model year, vehicle size and body type. Autonomous emergency braking and lane departure warning generally occur together, making it difficult to tease apart their individual effects. Blind spot detection was associated with a 14% reduction in crashes after controlling for the presence of autonomous emergency braking and lane departure warning (HR =0.86; 95% CI, 0.744–0.99). Differences were observed by vehicle type and crash type. The combined effect of autonomous emergency braking and lane departure warning was greater in newer model vehicles: Equipped vehicles were 13% less likely to crash (HR =0.87; 95% CI, 0.79–0.95) among 2014 model year vehicles versus 34% less likely to crash (HR =0.66; 95% CI, 0.57–0.77) among 2017 model year vehicles.Conclusion: This robust cohort study contributes to the growing evidence on the effectiveness of ADAS technologies. 相似文献
32.
Lars Guenther Peter Weingart Corlia Meyer 《Environmental Communication: A Journal of Nature and Culture》2018,12(8):1046-1061
ABSTRACTIn science communication, a prerequisite for reaching different parts of a society is to find out how these publics experience and interpret science. Since rural South African publics are perceived to exhibit a large cultural distance to science, the present exploratory study aimed to know in more detail how rural South Africans perceive and understand science in their local and social contexts. Theoretical notions on cultural distance and the methodological approach of segmentation studies were considered. Semi-structured interviews with rural South Africans were carried out in four towns (n?=?52) that differ with respect to having a large scientific installation in their vicinity, or not. Sensitively comparing local and social contexts helped identifying three different publics who differed regarding their perceptions of science; however, the large scientific installations only made a difference in perceptions for those publics who were generally less exposed to and less knowledgeable about science. 相似文献
33.
34.
35.
Assessment of Presence of Heavy Metals and Other Pollution Burden Parameters and Their Effect on Water Quality in Benin City,Edo State 下载免费PDF全文
An assessment of the heavy metal content and biological pollution burden of an abattoir dumpsite, an automobile carwash, the Ikpoba River, and a private water borehole located near the abattoir dumpsite was conducted in Benin City in Southern Nigeria, during the rainy and dry seasons. The water samples’ pH was lower than the permissible values, with the river water displaying color and possessing a slight odor. Iron concentrations exceeded the permissible limits for drinking water at all four of the sampling stations in the study area, although not in samples collected from the control station, station 5, a public water borehole that is located some distance away. Lead values were higher than drinking water standards in the samples collected from stations 1 through 4, with some exceptions during the rainy season. Copper, nickel, arsenic, chromium, and aluminum were detected in three out of the four sampling stations located within the study area. However, these metals were detected at levels that were within regulatory limits. The detection of three metals (iron, lead, and zinc) within the study area at levels exceeding drinking water limits suggested that a complete cycle of movement of pollutants into the sampling stations had occurred. Significant biological presences were also detected, as the Ikpoba River water had a standard plate count (SPC) of 130 most probable number (MPN) and a 22 MPN presumptive coliform count (PCC) or 22 MPN. However, Escherichia coli (E. coli) confirmatory tests recorded less than 2 MPN in both seasons. The study has shown that the quality of water in the river may be compromised by effluent discharges from the dumpsite and the carwash channel. Therefore, this situation requires more stringent enforcement of local environmental laws and maintenance of safe distances between domestic and industrial waste sources and domestic or private water wells. 相似文献
36.
Hydroponic root mats for wastewater treatment—a review 总被引:2,自引:0,他引:2
Zhongbing Chen Diego Paredes Cuervo Jochen A. Müller Arndt Wiessner Heinz Köser Jan Vymazal Matthias Kästner Peter Kuschk 《Environmental science and pollution research international》2016,23(16):15911-15928
Hydroponic root mats (HRMs) are ecotechnological wastewater treatment systems where aquatic vegetation forms buoyant filters by their dense interwoven roots and rhizomes, sometimes supported by rafts or other floating materials. A preferential hydraulic flow is created in the water zone between the plant root mat and the bottom of the treatment system. When the mat touches the bottom of the water body, such systems can also function as HRM filter; i.e. the hydraulic flow passes directly through the root zone. HRMs have been used for the treatment of various types of polluted water, including domestic wastewater; agricultural effluents; and polluted river, lake, stormwater and groundwater and even acid mine drainage. This article provides an overview on the concept of applying floating HRM and non-floating HRM filters for wastewater treatment. Exemplary performance data are presented, and the advantages and disadvantages of this technology are discussed in comparison to those of ponds, free-floating plant and soil-based constructed wetlands. Finally, suggestions are provided on the preferred scope of application of HRMs. 相似文献
37.
Quantifying the squeezing or stretching of fisheries as they adapt to displacement by marine reserves 下载免费PDF全文
The designation of no‐take marine reserves involves social and economic concerns due to the resulting displacement of fishing effort, when fishing rights are removed from those who traditionally fished within an area. Displacement can influence the functioning of the fishery and success of the reserve, yet levels of displacement are seldom quantified after reserve implementation and very rarely before that. We devised a simple analytical framework based on set theory to facilitate reserve placement. Implementation of the framework requires maps of fishing grounds, fishing effort, or catch per unit effort for at least 2 years. The framework quantifies the level of conflict that a reserve designation might cause in the fishing sector due to displacement and the opportunities to offset the conflict through fisher spatial mobility (i.e., ability of fishers to fish elsewhere). We also considered how the outputs of the framework can be used to identify targeted management interventions for each fishery. We applied the method in Honduras, where the largest marine protected area in Central America is being placed, for which spatial data on fishing effort were available for 6 fisheries over 3 years. The proposed closure had a greater negative impact on the shrimp and lobster scuba fisheries, which concentrated respectively 28% and 18% of their effort inside the reserve. These fisheries could not accommodate the displacement within existing fishing grounds. Both would be forced to stretch into new fishing grounds, which are available but are of unknown quality. These stakeholders will likely require compensation to offset costly exploratory fishing or to travel to fishing grounds farther away from port. 相似文献
38.
Michele Citterio Mikael K. Sejr Peter L. Langen Ruth H. Mottram Jakob Abermann Signe Hillerup Larsen Kirstine Skov Magnus Lund 《Ambio》2017,46(1):146-159
Terrestrial freshwater runoff strongly influences physical and biogeochemical processes at the fjord scale and can have global impacts when considered at the Greenland scale. We investigate the performance of the HIRHAM5 regional climate model over the catchments delivering freshwater to Tyrolerfjord and Young Sound by comparing to the unique Greenland Ecological Monitoring database of in situ observations from this region. Based on these findings, we estimate and discuss the fraction of runoff originating from glacierized and non-glacierized land delivered at the daily scale between 1996 and 2008. We find that glaciers contributed on average 50–80% of annual terrestrial runoff when considering different sections of Tyrolerfjord–Young Sound, but snowpack depletion on land and consequently runoff happens about one month earlier in the model than observed in the field. The temporal shift in the model is a likely explanation why summer surface salinity in the inner fjord did not correlate to modelled runoff. 相似文献
39.
The humanitarian common logistic operating picture: a solution to the inter‐agency coordination challenge 下载免费PDF全文
Although significant progress has been made in developing the practice of humanitarian logistics, further improvements in efficiency and effectiveness have the potential to save lives and reduce suffering. This paper explores how the military/emergency services’ concept of a common operating picture (COP) can be adapted to the humanitarian logistics context, and analyses a practical and proven approach to addressing the key challenge of inter‐agency coordination and decision‐making. Successful adaptation could provide the mechanism through which predicted and actual demands, together with the location and status of material in transit, are captured, evaluated, and presented in real time as the basis for enhanced decision‐making between actors in the humanitarian supply network. Through the introduction of a humanitarian logistics COP and its linkages to national disaster management systems, local communities and countries affected by disasters and emergencies will be better placed to oversee and manage their response activities. 相似文献
40.
Peter M. Haas 《中国人口.资源与环境(英文版)》2017,15(3):186-188
<正>1.Introduction And now we have Parxit.On 1 June 2017,President Trump issued the highly unpopular announcement that the United States will withdraw from the 2015 Paris Agreement on Climate Change.In this brief piece,I will try to explain the reasons for this nearly unprecedented act of foreign policy folly(Ronald Reagan did pull out of the Law of the Sea 相似文献