全文获取类型
收费全文 | 854篇 |
免费 | 99篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 733篇 |
废物处理 | 1篇 |
环保管理 | 50篇 |
综合类 | 25篇 |
基础理论 | 37篇 |
污染及防治 | 12篇 |
评价与监测 | 5篇 |
社会与环境 | 2篇 |
灾害及防治 | 90篇 |
出版年
2023年 | 15篇 |
2022年 | 35篇 |
2021年 | 48篇 |
2020年 | 52篇 |
2019年 | 42篇 |
2018年 | 22篇 |
2017年 | 20篇 |
2016年 | 26篇 |
2015年 | 50篇 |
2014年 | 32篇 |
2013年 | 32篇 |
2012年 | 49篇 |
2011年 | 56篇 |
2010年 | 49篇 |
2009年 | 43篇 |
2008年 | 34篇 |
2007年 | 53篇 |
2006年 | 37篇 |
2005年 | 28篇 |
2004年 | 28篇 |
2003年 | 20篇 |
2002年 | 16篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 27篇 |
1998年 | 19篇 |
1997年 | 11篇 |
1996年 | 17篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 2篇 |
排序方式: 共有955条查询结果,搜索用时 467 毫秒
251.
252.
253.
尾矿坝溃坝模型研究及应用 总被引:8,自引:4,他引:4
根据多个大坝的实际溃决资料,提出尾矿坝溃坝的数学模型,该模型考虑尾矿的物理力学性质及其在流动中的变形,适合溃坝砂流下泄流量变幅大的特点。并就尾矿坝溃坝后泥石流对坝下游的影响提出预测的方法,该方法确定了泄砂总量、溃坝口平均宽度、坝址最大砂流量、坝址流量过程线等溃坝的重要参数。最后利用数学模型对某尾矿库溃坝砂流进行了预测,并指出该坝下游人员的撤离高程,为防灾减灾以及保护人民生命财产安全等起到了积极作用。 相似文献
254.
大型社会活动安全风险评估指标研究 总被引:3,自引:1,他引:2
在对大型社会活动特点及其活动增长趋势分析的基础上,通过对大型社会活动典型伤亡事故的统计,将事故发生直接原因归纳为突发自然灾害、设备设施故障、管控措施失误、疏散设施不符合要求、人为事件和其他因素6类;根据风险管理理论,针对大型社会活动安全风险,从人-机-环-管安全系统工程的观点出发,以准确反映大型社会活动的本质特征和事故预防与控制为目标、尽可能量化为原则,提出具有4个一级指标、9个二级指标和24个三级指标的大型社会活动安全风险评估指标体系和评估依据,并对周边环境、人群密度、疏散速度及人群状况指标进行量化分级。 相似文献
255.
Vestergaard Peter 《Journal of Coastal Conservation》2001,7(2):117-128
The initial recovery of vegetation after a wildfire in a coastal dune area in NW Jutland, Denmark, was studied over a 5-yr
period by means of permanent plots representing various dune communities along a topographical gradient.
The impact of the fire varied with the position of the plots. Fens and south-facing dunes were little affected while dune
heath plots were severely affected including loss of the O-horizon. Post-fire conditions included presence of remaining soil
organic matter, a soil seed bank and surviving below-ground plant parts. The soil surface remained stable during the study
period.
The initial five years of recovery comprised of an initial three-year recruitment phase during which cover and number of species
increased and the quantitative species composition changed markedly, followed by two years of a declining rate of change.
38 species of vascular plants were recorded, 35 are regular components in dune, dune heath and heath fen and were recruited
from the seed bank, from locally dispersed seeds and/or by sprouting from surviving vegetative parts. The remaining three
species were ‘aliens’, dispersed from sources outside the area. Crustose lichens had an important role in the initial recovery
by stabilizing the surface and probably inhibiting seed germination, whereas mosses mostly had a subordinate role.
The seral position of the plots, as well as the expected time needed for full recovery of pre-fire vegetation, vary with topography
and initial soil conditions. Five years after the fire the fen and the south-facing dune probably need less than a decade
for full recovery. The remaining plots are judged to be relatively early seral; their full recovery into mature dry or moist
dune heath vegetation and O-horizon is expected to need several centuries. 相似文献
256.
磁悬浮车辆中人员紧急疏散的仿真研究 总被引:4,自引:4,他引:0
为了对研制的八达岭低速磁浮试验列车人员疏散安全性进行评估,考虑从磁浮车辆的空间布局和人员紧急疏散的特点,在现有的元胞自动机模型和行人流模型基础上,通过人员动态调整自身速度、动态修正人员行为等技术,建立了一种基于车辆环境约束以及人员行为特性的元胞自动机模型。该模型具有人员速度可变、能以自组织现象修正人员行为的特点,经过比较验证,模型的仿真过程更加接近真实情况,仿真结果与一般经验公式得到结果相吻合。以我国正在研制的八达岭低速磁浮试验列车为仿真对象,对车辆布局对其人员的安全疏散的影响进行了计算机仿真和分析,找出了影响人员疏散效率和时间的关键因素,为设计改进提供了依据。 相似文献
257.
Bambang Hero Saharjo 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):135-146
Transboundary haze pollution from smoke from land preparation fires has become a perennial problem in Indonesia, especially
in the last 10 years during the dry season. Most of that smoke originates from illegal land preparation fires for oil palm
and industrial forest plantation as well as from shifting cultivation, which is usually blamed for the smoke. In order to
understand the role of fire in shifting cultivation areas dominated by peat soils, research was conducted during the dry season
of 2001 on land belonging to the community of Pelalawan village, Pelalawan district, Riau province, Indonesia. The research
showed that burning did not affect all peat areas equally. No peat was burned on a fibric site, while burning on a hemic site
varied in depth from 6.0 cm to 12.6 cm, and on a sapric site from 15.4 cm to 31.9 cm. Further, on the fibric site only phosphorus
increased significantly following burning, while on the hemic only the base saturation increased; on the sapric site, however,
both base saturation and phosphorus increased compared to the condition before burning. These data show that if fire is continues
to be used for land preparation in peat areas, peat becomes critically endangered. 相似文献
258.
标准受限空间内细水雾熄灭煤油火的实验和数值模拟 总被引:1,自引:2,他引:1
在3.0m×3.0m×2.8m标准受限空间内,采用煤油模拟池火,火灾功率设定为195kW,进行了一系列细水雾灭火试验。对灭火时间做了详细记录,并实验研究了灭火时间的重现性及其相关因素。采用M-9000燃烧分析仪对细水雾施加前后火灾烟气(如氧气、二氧化碳、一氧化碳、一氧化氮、二氧化氮、二氧化硫)的浓度进行了在线测量。其结果表明:细水雾灭火系统熄灭煤油火的时间均在20s以内,灭火时间重现性保持在91.9%以内;施加细水雾后,氧气浓度降低,一氧化碳浓度升高,燃烧更加不完全。采用FDS模拟了细水雾熄灭煤油火,预测的温度场和灭火时间与实验结果吻合较好。 相似文献
259.
The complexity of the evacuation process is associated with the flow of occupants through various egresses available inside the building. Several methods and algorithms are now available to analyse the problem related to evacuation. In the present paper an algorithm, evacuation discrete time model (EDTM) has been presented to analyse the building egress evacuation time problem with previous works. The algorithm is based on the crowd flow theory and uses discrete computational approach to identify various widths of egresses available for movement of the people, which is more accurate and practicable because the crowd flow rate is variable. The developed model has been compared with an existing model to show the capabilities of the developed algorithm. A case of stadium stand egress is chose for the validity of EDTM, and a comparison of EDTM, previous model and computer simulation indicates that both the EDTM and the simulation curves were found to give better predictions than the previous model. Based upon the comparison analysis with stranded crowd and evacuation crowd at a certain time, EDTM shows great value in explaining the cause of stampede-trampling and crushing incident of egress or narrow passage zone. 相似文献
260.
系统分析了客运专线联合运输存在的主要安全问题及其产生原因。指出旅客联合运输安全问题的关键在各种运输方式的衔接处,其核心因素包括:信息不共享、安全管理缺乏统一规范、交通枢纽软硬件设施有缺陷3个方面,进而针对上述缺陷问题提出相应措施,采用安全审计方法来具体地实现对联合运输安全问题的整改、提高系统安全性能,并对交通枢纽疏散进行案例分析。 相似文献