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361.
The paper examines the copper consumption-economic growth nexus for 16 rich economies from the period 1966 to 2010. Various generations of panel unit root and cointegration tests are applied. Both series are found to be integrated of order one. Evidence of cointegration is found especially when controlling for breaks and long-run cross-sectional dependence. Causality is investigated using a vector error-correction mechanism (VECM) framework. At individual level, unidirectional causality running from economic growth to copper consumption is unraveled for Finland, France and UK in the long-run. Unidirectional causality is also found running from copper consumption to economic growth for Spain. Long-run bi-directionality between economic growth and copper consumption is found for Belgium, Greece, Italy, Japan and South Korea. The neutrality hypothesis holds for Australia, Austria, Canada, Netherlands, Portugal, Sweden and USA in the long-run. Taken as a whole, panel causality test reveals a long-run unidirectional causality running from economic growth to copper consumption.  相似文献   
362.
To examine the impact of the change in forward pricing mechanism on the volatility of iron ore spot prices, we model the iron ore daily price of Platts IODEX from October 7, 2008 to September 21, 2012. The identified iron ore spot price tends to be less volatile after the introduction of quarterly pricing mechanism. Our main approaches are as follows: (i) to decompose the spot price of Platts IODEX into two subsamples and relate the result of the structural break to the date of the switch in the iron ore forward pricing mechanism; (ii) to apply the EGARCH (1, 1) model to simultaneously capture the long memory and the asymmetric effect on the volatility of the iron ore spot price; and (iii) to delineate the news impact curve to further interpret the asymmetric effect.  相似文献   
363.
A full probabilistic Explosion Risk Analysis (ERA) is commonly used to establish overpressure exceedance curves for offshore facilities. This involves modelling a large number of gas dispersion and explosion scenarios. Capturing the time dependant build up and decay of a flammable gas cloud size along with its shape and location are important parameters that can govern the results of an ERA. Dispersion simulations using Computational Fluid Dynamics (CFD) are generally carried out in detailed ERA studies to obtain these pieces of information. However, these dispersion simulations are typically modelled with constant release rates leading to steady state results. The basic assumption used here is that the flammable gas cloud build up rate from these constant release rate dispersion simulations would mimic the actual transient cloud build up rate from a time varying release rate. This assumption does not correctly capture the physical phenomena of transient gas releases and their subsequent dispersion and may lead to very conservative results. This in turn results in potential over design of facilities with implications on time, materials and cost of a project.In the current work, an ERA methodology is proposed that uses time varying release rates as an input in the CFD dispersion simulations to obtain the fully transient flammable gas cloud build-up and decay, while ensuring the total time required to perform the ERA study is also reduced. It was found that the proposed ERA methodology leads to improved accuracy in dispersion results, steeper overpressure exceedance curves and a significant reduction in the Design Accidental Load (DAL) values whilst still maintaining some conservatism and also reducing the total time required to perform an ERA study.  相似文献   
364.
臭氧浓度升高对土壤-冬小麦系统CO2排放的影响   总被引:1,自引:1,他引:1  
通过田间试验,采用静态箱-气相色谱法测定CO2排放通量,研究臭氧(O3)浓度升高对土壤-冬小麦系统CO2排放的影响.结果表明,O3浓度升高对CO2排放的季节变化模式无明显影响.在返青期和拔节孕穗期,O3浓度升高显著降低了土壤-冬小麦系统的CO2排放通量;在抽穗成熟期,O3浓度100 nL·L-1处理对CO2排放通量没有...  相似文献   
365.
淡水发光菌对工业废水的生物毒性研究   总被引:1,自引:1,他引:1  
发光菌作为指示生物用于污染源水体的生物毒性测定具有快速、灵敏、低廉等优点,现已广泛用于环境毒物综合急性毒性测定、筛查、监测及特异毒物监测中.文章利用淡水发光菌Q67对东北地区各行业典型企业的出水口进行急性毒性试验,同时结合化学指标进行了综合评估,试验结果表明:急性毒性试验和化学指标并非在任何水体都相关,但急性毒性试验是化学试验的必要补充.  相似文献   
366.
Mineral development has contributed greatly to China's economic and social development. Many challenges remain, however, including environmental pollution and resource waste in practice, as well as a dearth of systematic theoretical research. The goal of this study is to analyze the economic and social effects of various mineral developments in China from diversified perspectives, so as to provide the basis for the formulation of China's mineral development policy. The input–output effects, industrial linkage effects and income distribution effects of different mining industries are quantitatively analyzed by adopting basic hypotheses of input–output economics, industrial linkage model and income distribution antitheses based on the latest available official data from China Statistical Yearbook from 2004 to 2010 and the 2007 Input–Output Table of China. The empirical results obtained in this study indicate that all mineral development industries, especially coal mining and washing, and petroleum and natural gas extraction industries, have given a strong impetus to the increase of China's fixed asset investment and GDP. Moreover, they have provided a large number of jobs, thereby alleviating ongoing employment pressure, and they have also played a positive role in promoting China's technology investment. The analysis of industrial linkages demonstrates that mining industries are basic to the national economy and produce a significant impetus to its downstream industries, but create weak pull effects in terms of national economic development. From the perspective of income distribution, mining industries play an important role in increasing China's fiscal revenue and per capital income. Hence, China's mineral development policy should (1) encourage additional investment in technology for exploration and development to insure sufficient supply and expand the input effects; (2) attract additional talent to work in remote regions; (3) optimize the industrial structure and promote the industrial transformation in resource regions; (4) adjust the interest distribution between the central and local governments to enable the local regions to become more self-sufficient; and (5) enhance the legal environment so that companies can more readily undertake their social responsibilities voluntarily.  相似文献   
367.
20种水溶性有机溶剂对发光菌的毒性效应   总被引:9,自引:0,他引:9       下载免费PDF全文
以新型淡水发光菌——青海弧菌Q67(Vibrio-qinghaiensis sp.Q67)为检测生物,应用VeritasTM微孔板光度计测定了甲醇等20种常见水溶性有机溶剂对Q67的毒性效应.结果表明,乙腈、甲醇、乙醇、丙酮、乙醚、四氢呋喃和异丙醇7种有机溶剂具有非单调J型剂量-效应关系,其他13种为典型S型剂量-效应关系.分别采用Biphasic、Logit和Weibull等非线性函数进行曲线模拟,利用模拟函数可有效估算有机溶剂的各个效应浓度Ecx值.不同组成和结构的有机溶剂对淡水发光菌的毒性效应不同,官能团相同的直链溶剂含碳数越多毒性越大.  相似文献   
368.
目的 研究海洋大气环境下氯离子在Q235钢表面的沉积分布规律。方法 使用便携式X射线荧光光谱仪测试Q235钢在海南岛不同地点大气环境暴露后的表面氯离子沉积,然后采用插值算法绘制氯离子在Q235钢表面沉积分布图和海南岛不同地点氯离子在Q235钢表面平均沉积量分布图,并根据氯离子沉积分布图分析氯离子在Q235钢表面的沉积量分布规律。结果 氯离子在Q235钢表面呈不均匀分布特征。在环境暴露试验前6个月,Q235钢表面氯离子含量逐渐增加;暴露6~12个月,Q235钢表面的氯离子含量总体变化不大。从整个海南岛看,内陆地区氯离子在Q235钢表面的沉积量低,而在沿海环岛区域的沉积量高。在海南岛沿海地区,Q235钢表面氯离子沉积量随季风风向的变化而变化。结论 氯离子在Q235钢表面呈不均匀沉积分布,Q235钢表面氯离子沉积量在海南岛不同地点呈“中间低、两边高”的沉积分布规律,内陆地区沉积量低,而沿海环岛区域沉积量高,并且沿海地区的氯离子沉积易受季风风向的影响。  相似文献   
369.
MIL-53(Fe) was successfully prepared and deposited on the surface carboxylated polyester (PET) fiber by an optimized conventional solvothermal or industrialized high temperature pressure exhaustion (HTPE) process to develop a PET fiber supported MIL-53(Fe) photocatalyst ([email protected]) for the degradation of polyvinyl alcohol (PVA) in water under light emitting diode (LED) visible irradiation. On the basis of several characterizations, [email protected] was tested for the photocalytic ability and degradation mechanism. It was found that temperature elevation significantly enhanced the formation and deposition of MIL-53(Fe) with better photocatalytic activity. However, higher temperature than 130°C was not in favor of its photocatalytic activity. Increasing the number of surface carboxyl groups of the modified PET fiber could cause a liner improvement in MIL-53(Fe) loading content and photocatalytic ability. High visible irradiation intensity also dramatically increased photocatalytic ability and PVA degradation efficiency of [email protected] Na2S2O8 was used to replace H2O2 as electron acceptor for further promoting PVA degradation in this system. [email protected] prepared by HTPE process showed higher MIL-53(Fe) loading content and slightly lower PVA degradation efficiency than that prepared by solvothermal process at the same conditions. These findings provided a practical strategy for the large-scale production of the supported MIL-53(Fe) as a photocatalyst in the future.  相似文献   
370.
目的 探究我国典型湿热海洋大气环境特征,以Q235钢为标杆材料,评估并可视化展示海南湿热海洋大气环境严酷度。方法 以海南岛为典型湿热海洋地区,基于分布全岛全域的13个站点开展自然大气环境试验,采集各站点大气环境数据与Q235钢材料性能数据。通过分析表观形貌、腐蚀质量损失等性能,探究Q235钢在海南大气环境的腐蚀行为规律及其在全岛不同区域的腐蚀程度差异。基于大气环境因素与Q235钢腐蚀行为间相关性研究,筛选腐蚀敏感环境因素,构建“腐蚀质量损失-敏感环境因素”映射模型。基于Q235钢海南各地区腐蚀质量损失数据,通过Griddata插值,计算绘制腐蚀质量损失分布地图。结果 掌握了Q235钢在海南各地区腐蚀行为差异,可视化展示了海南大气腐蚀严酷度。结论 影响Q235钢海南地区腐蚀的敏感环境因素为离海距离及湿度大于80%的时间。海南地区沿海岸及东部地区大气环境腐蚀严酷度高,中部及西部地区严酷度低。  相似文献   
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