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141.
为获得有限应急资源条件下满足多个目标的最优分配方案,提高事故应急救援效率,对某化工园区化工事故的应急物资分配进行了研究。在传统线性规划基础上引入区间数描述物资需求量和物资运输时间的不确定性,并以应急物资分配的经济性、时效性和公平性为目标,建立了多目标线性区间规划模型,并将所建模型应用于以化工园区为背景的化工事故中,同时为验证该模型的有效性,将提出的多目标区间规划模型与多目标确定性规划模型相比较。结果表明,区间规划模型得到的结果比较可观,可为相关决策单位应急资源分配提供参考,同时区间规划也是对传统资源配置分析方法的有益补充。 相似文献
142.
为量化抽出式通风机及其数量对排烟道与行车道内流量分配的影响,提出1个新的量化指标——通风排烟系统性能系数,即为抽出式与压入式通风机组合功耗与排烟体积流量的比值。为确立通风排烟系统性能系数,依托某过海区间隧道,搭建隧道通风排烟模型实验系统,测定排烟道与行车道所构成的风道内流动参数。结果表明:以吊顶排烟口为镜像面,行车道静压对称分布;对于行车道速度而言,双压二抽表现为对称分布,双压一抽为近对称,双压零抽为偏置分布;偏置分布的排烟道速度出现在双压一抽中,近对称属于双压零抽,对称显现于双压二抽。将数据进行分析计算后可知,性能系数最低的是双压零抽两通风机组合。 相似文献
143.
Risk-based inspection for large-scale crude oil tanks 总被引:1,自引:0,他引:1
Jian Shuai Kejiang HanXuerui Xu 《Journal of Loss Prevention in the Process Industries》2012,25(1):166-175
Periodic Internal Inspection Method often results in under-inspection or over-inspection for large-scale crude oil tank. Therefore, how to determine reasonable internal inspection interval (INTII) has great significance on balancing the safe operation requirement and inspection cost for crude oil tanks. Here, RBI (risk-based inspection) technology is used to quantitatively assess the risk of crude oil tanks in an oil depot in China. The risk comparison between tank shell and bottom shows that the risk of tank depends on the risk of tank bottom. The prediction procedure of INTII for crude oil tanks is also presented. The INTII predicted by RBI method is gradually extended with the increasing of the acceptable risk level. The method to determine the acceptable risk of crude oil tanks is proposed, by which 3.54E+04 are taken as the acceptable risk of the oil depot. The safety factor of 0.8 is proposed to determine the final INTIIs for 18 crude oil tanks. The INTII requirement in China code SY/T 5921, 5-7 years, is very conservative and lower than predicted service life of tanks. The INTIIs predicted by Gumbel method are smaller than by RBI method for tanks with short INTII. Therefore, this paper recommends RBI method to predict the INTII for crude oil tanks. 相似文献
144.
Skarlatos D 《Environmental monitoring and assessment》2003,85(1):55-67
A common practice in random noise measurements is to assume that the noise samples are normally distributed. Since the sound pressure level (L
p) is related with the sound energy by a non linear equation, the distribution of the two variables will be different. If one assumes that the probability density function (pdf) of L
p is normal, the pdf of noise energy is not and vice versa. A simple criterion based on statistical properties of sampled noise can be used for the determination of the kind of distribution of the measured noise. The case in which the noise energy emitted by the source, and the case in which the measured noise level is normally distributed are examined. For each case confidence intervals of the calculated equivalent level are calculated. 相似文献
145.
Kisei Kinoshita Wang Ning Zhang Gang Andrew Tupper Naoko Iino Satoshi Hamada Satoshi Tsuchida 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):89-100
Monitoring of Asian dust at two stations in Changchun, Jilin Province in northeast China, and Kagoshima, southwest Japan,
is discussed. In Changchun, interval records were made with digital and video cameras from 18 March 2003. In Kagoshima, a
web camera system to monitor volcanic clouds has been working since December 2000, which also provides data for studies of
dust. A heavy dust episode on 11 November 2002, affecting both stations, was detected using 11 and 12 μm channels of NOAA/AVHRR.
We observed dust in Changchun on 26 March, 7, 14–16 April, 1–2, 8, 10, 19 May, 8, 23 June, and 12 July in 2003. The observed
images corresponded well to NOAA/AVHRR imagery and with 8.6, 11 and 12 μm Terra/MODIS results, although conditions were too
cloudy for satellite verification in some cases. 相似文献
146.
张玉青 《中国环境管理干部学院学报》2003,13(2):54-57
本文分析了基本抽样程序,并用来解决环境监测的抽样优化问题。抽样过程形成马尔可夫链,通过划分接收水平和抽样区间建立抽样策略。计算每一组策略的目标函数的取值,找到备选策略中最小成本抽样策略即最优抽样策略。 相似文献
147.
ABSTRACT: A simple simulation type approach and a statistical method are proposed for determining the confidence interval of the T‐year frequency rainfall percentiles (or precipitation extremes) for generalized extreme value (GEV) distributions. The former method is based on the Monte Carlo testing procedure. To generate realizations, the covariance structure of the three parameters of GEV is investigated using an observed information matrix of the likelihood function. For distributions with realistic parameters, the correlation between the location and the scale parameters is practically constant when the shape parameter varies around values close to its optimal value. The latter method is based on likelihood ratio statistics. In the case where the joint confidence surface for shape parameters and estimates is plotted with lines of best estimates, the region where the estimated best percentile value can be chosen as a possible estimate is part of the joint confidence surface. The projection of this bounded region on axis of percentile is defined as the effective confidence interval in this research. The use of this effective interval as the confidence interval of the percentile of T‐year frequency rainfall is particularly recommended because it is stable for T and it reflects variations in all three parameters of GEV appropriately. 相似文献
148.
工业企业噪声环境影响评价中的测点布设与测量、预测时段的选择 总被引:1,自引:0,他引:1
指出工业企业噪声环境影响评价中,由于测点与测量时段选择的不妥,导致测量及预测值“以偏代全”的结果;提出了测点合理布设与测量、预测时段科学选择的原则,以使测量与预测结果能较好地符合项目建成前后噪声环境实际状况。 相似文献
149.
150.
Barry R. Taylor Hal R. Hamilton Gordon Macdonald 《Journal of the American Water Resources Association》1993,29(2):235-247
ABSTRACT: River solute loads have seldom been measured in very large, complex drainage basins, nor have the methods of calculating loads been critically examined. For sites in the Saskatchewan River Basin, Canada, rating curves were poor predictors of solute loads because correlations between discharge and total solutes concentration were weak (R2 < 0.05 in most cases) and suffered from hysteresis. In contrast, the interval method produced reliable estimates in all seasons and sites tested, and was little affected by sampling schedule. The limit of precision (SE) for estimates of mean annual or seasonal solute load was 10–15 percent of the mean (5 percent in very small basins), reached with 10 years or more of data. Two-thirds or more of total annual solute load was transported during the open-water season, but the proportion carried during winter increased from 8 percent to 34 percent from the upstream to the downstream end of the basin, due to reservoirs retaining and mixing water. Annual loads of total solutes varied from 6.2 × 104 tonnes in foothills tributaries to almost 4.0 × 106 tonnes in the Saskatchewan River near the mouth. But, on an areal basis, the mountain and foothills region was the dominant solute source, producing 43–97 tonnes/km2/yr, compared with only 3–22 tonnes/km2/yr for prairie rivers. This difference is a consequence of greater rainfall and, hence, more rapid erosion in the mountains. 相似文献