全文获取类型
收费全文 | 1848篇 |
免费 | 195篇 |
国内免费 | 13篇 |
专业分类
安全科学 | 1424篇 |
废物处理 | 5篇 |
环保管理 | 77篇 |
综合类 | 223篇 |
基础理论 | 68篇 |
污染及防治 | 6篇 |
评价与监测 | 11篇 |
社会与环境 | 5篇 |
灾害及防治 | 237篇 |
出版年
2023年 | 27篇 |
2022年 | 60篇 |
2021年 | 69篇 |
2020年 | 92篇 |
2019年 | 72篇 |
2018年 | 36篇 |
2017年 | 60篇 |
2016年 | 46篇 |
2015年 | 70篇 |
2014年 | 60篇 |
2013年 | 67篇 |
2012年 | 169篇 |
2011年 | 142篇 |
2010年 | 97篇 |
2009年 | 109篇 |
2008年 | 60篇 |
2007年 | 144篇 |
2006年 | 162篇 |
2005年 | 96篇 |
2004年 | 97篇 |
2003年 | 67篇 |
2002年 | 50篇 |
2001年 | 57篇 |
2000年 | 25篇 |
1999年 | 23篇 |
1998年 | 27篇 |
1997年 | 16篇 |
1996年 | 21篇 |
1995年 | 1篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有2056条查询结果,搜索用时 343 毫秒
141.
Individual risk analysis of high-pressure natural gas pipelines 总被引:1,自引:0,他引:1
Young-Do Jo Daniel A. Crowl 《Journal of Loss Prevention in the Process Industries》2008,21(6):589-595
Transmission pipelines carrying natural gas are not typically within secure industrial sites, but are routed across land out of the ownership of the pipeline company. If the natural gas is accidentally released and ignited, the hazard distance associated with these pipelines to people and property is known to range from under 20 m for a smaller pipeline at lower pressure to up to over 300 m for a larger pipeline at higher pressure. Therefore, pipeline operators and regulators must address the associated public safety issues.This paper focuses on a method to explicitly calculate the individual risk of a transmission pipeline carrying natural gas. The method is based on reasonable accident scenarios for route planning related to the pipeline's proximity to the surrounding buildings. The minimum proximity distances between the pipeline and buildings are based on the rupture of the pipeline, with the distances chosen to correspond to a radiation level of approximately 32 kW/m2. In the design criteria for steel pipelines for high-pressure gas transmission (IGE/TD/1), the minimum building proximity distances for rural areas are located between individual risk values of 10−5 and 10−6. Therefore, the risk from a natural gas transmission pipeline is low compared with risk at the building separated minimum distance from chemical industries. 相似文献
142.
143.
144.
145.
D. G. NIMMO L. M. SPENCE‐BAILEY R. S. TAYLOR M. F. CLARKE A. F. BENNETT 《Conservation biology》2013,27(2):345-353
Fire influences the distribution of fauna in terrestrial biomes throughout the world. Use of fire to achieve a mosaic of vegetation in different stages of succession after burning (i.e., patch‐mosaic burning) is a dominant conservation practice in many regions. Despite this, knowledge of how the spatial attributes of vegetation mosaics created by fire affect fauna is extremely scarce, and it is unclear what kind of mosaic land managers should aim to achieve. We selected 28 landscapes (each 12.6 km2) that varied in the spatial extent and diversity of vegetation succession after fire in a 104,000 km2 area in the semiarid region of southeastern Australia. We surveyed for reptiles at 280 sites nested within the 28 landscapes. The landscape‐level occurrence of 9 of the 22 species modeled was associated with the spatial extent of vegetation age classes created by fire. Biogeographic context and the extent of a vegetation type influenced 7 and 4 species, respectively. No species were associated with the diversity of vegetation ages within a landscape. Negative relations between reptile occurrence and both extent of recently burned vegetation (≤10 years postfire, n = 6) and long unburned vegetation (>35 years postfire, n = 4) suggested that a coarse‐grained mosaic of areas (e.g. >1000 ha) of midsuccessional vegetation (11–35 years postfire) may support the fire‐sensitive reptile species we modeled. This age class coincides with a peak in spinifex cover, a keystone structure for reptiles in semiarid and arid Australia. Maintaining over the long term a coarse‐grained mosaic of large areas of midsuccessional vegetation in mallee ecosystems will need to be balanced against the short‐term negative effects of large fires on many reptile species and a documented preference by species from other taxonomic groups, particularly birds, for older vegetation. Mosaicos de Fuego y la Conservación de Reptiles en una Región Propensa al Fuego 相似文献
146.
S. W. Hostetler 《Journal of the American Water Resources Association》1991,27(4):637-647
ABSTRACT: Steamboat Creek basin is an important source of timber and provides crucial spawning and rearing habitat for anadromous steelhead trout (Oncorhynchus mykiss). Because stream temperatures are near the upper limit of tolerance for the survival of juvenile steelhead, the possible long-term effect of clear-cut logging on stream temperatures was assessed. Twenty-year (1969–1989) records of summer stream temperature and flow from four tributaries and two reaches of Steamboat Creek and Boulder Creek (a nearby unlogged watershed) were analyzed. Logging records for the Steamboat Creek basin and air temperature records also were used in the analysis. A time-series model of the components of stream temperature (seasonal cycle of solar radiation, air temperature, streamflow, an autoregressive term of order 1, and a linear trend variable) was fitted to the water-temperature data. The linear trend variable was significant in all the fitted models except Bend Creek (a tributary fed by cool ground-water discharge) and Boulder Creek. Because no trends in either climate (i.e., air temperature) or streamflow were found in the data, the trend variable was associated with the pre-1969 loss and subsequent regrowth of riparian vegetation and shading canopies. 相似文献
147.
电缆火灾的危害及其防治对策 总被引:1,自引:0,他引:1
张俊卿 《中国安全科学学报》1994,4(2):59-62
简述电缆火灾的危害,分析电缆火灾的原因及特点,提出电缆火灾的防范措施和处理方法。 相似文献
148.
本文根据调查分析,指出建设城市防火安全系统的迫切性。阐述了建设城市防火安全系统的基本原理和规划方法。并探讨了城市防火安全系统的运用管理。 相似文献
149.
150.