全文获取类型
收费全文 | 543篇 |
免费 | 66篇 |
国内免费 | 120篇 |
专业分类
安全科学 | 101篇 |
废物处理 | 39篇 |
环保管理 | 52篇 |
综合类 | 350篇 |
基础理论 | 68篇 |
污染及防治 | 57篇 |
评价与监测 | 42篇 |
社会与环境 | 10篇 |
灾害及防治 | 10篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 12篇 |
2021年 | 17篇 |
2020年 | 17篇 |
2019年 | 11篇 |
2018年 | 11篇 |
2017年 | 20篇 |
2016年 | 25篇 |
2015年 | 22篇 |
2014年 | 38篇 |
2013年 | 37篇 |
2012年 | 42篇 |
2011年 | 56篇 |
2010年 | 30篇 |
2009年 | 41篇 |
2008年 | 24篇 |
2007年 | 33篇 |
2006年 | 34篇 |
2005年 | 25篇 |
2004年 | 34篇 |
2003年 | 22篇 |
2002年 | 22篇 |
2001年 | 24篇 |
2000年 | 31篇 |
1999年 | 17篇 |
1998年 | 18篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 9篇 |
1991年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有729条查询结果,搜索用时 31 毫秒
211.
采用类UV/Fenton法对模拟三唑磷废水进行处理。在模拟废水中人工投加H2O2和Fe^3+试剂能产生类Fenton试剂,类Fenton试剂在光照条件过程中可以产生大量活性羟基.OH,能够很好地氧化降解废水中的有机化合物。本方法可以有效的处理低浓度的含三唑磷的废水,提供三唑磷农药水样的UV/Fenton催化氧化过程的一级动力学方程。 相似文献
212.
Ahlstrom U 《Journal of Safety Research》2005,36(2):159-169
INTRODUCTION: Adverse weather conditions have a major impact on National Airspace System (NAS) operations. They create safety hazards for pilots, constrain the usable airspace for air traffic control (ATC), and reduce the overall capacity of the NAS. A system-wide dissemination of weather information to controllers could theoretically improve safety and efficiency. PROBLEM: However, it is currently unclear what weather information would be beneficial for tactical operations. Furthermore, no previous research has empirically evaluated optimal presentation designs for ATC weather displays. Ill-designed weather displays can cause safety hazards by presenting redundant information (i.e., by increasing the cognitive load) and display clutter (e.g., by interfering with the visual extraction of traffic data). METHOD: In the present paper, we outline our use of cognitive work analysis (CWA) techniques for the assessment of weather information needs for terminal controllers. RESULTS: Specifically, we describe how the CWA modeling tools helped us reveal instances in the terminal domain where weather information is lacking or insufficiently disseminated. We used our CWA results to drive the development of weather display concepts and to set up a high-fidelity simulation capability. IMPACT ON INDUSTRY: By means of high-fidelity simulations, we can empirically evaluate controller weather information needs in order to propose weather displays for increased aircraft safety and efficiency of terminal operations. 相似文献
213.
Most soils contain preferential flow paths that can impact on solute mobility. Solutes can move rapidly down the preferential flow paths with high pore-water velocities, but can be held in the less permeable region of the soil matrix with low pore-water velocities, thereby reducing the efficiency of leaching. In this study, we conducted leaching experiments with interruption of the flow and drainage of the main flow paths to assess the efficiency of this type of leaching. We compared our experimental results to a simple analytical model, which predicts the influence of the variations in concentration gradients within a single spherical aggregate (SSA) surrounded by preferential flow paths on leaching. We used large (length: 300 mm, diameter: 216 mm) undisturbed field soil cores from two contrasting soil types. To carry out intermittent leaching experiments, the field soil cores were first saturated with tracer solution (CaBr2), and background solution (CaCl2) was applied to mimic a leaching event. The cores were then drained at 25- to 30-cm suction to empty the main flow paths to mimic a dry period during which solutes could redistribute within the undrained region. We also conducted continuous leaching experiments to assess the impact of the dry periods on the efficiency of leaching. The flow interruptions with drainage enhanced leaching by 10–20% for our soils, which was consistent with the model's prediction, given an optimised “equivalent aggregate radius” for each soil. This parameter quantifies the time scales that characterise diffusion within the undrained region of the soil, and allows us to calculate the duration of the leaching events and interruption periods that would lead to more efficient leaching. Application of these methodologies will aid development of strategies for improving management of chemicals in soils, needed in managing salts in soils, in improving fertiliser efficiency, and in reclaiming contaminated soils. 相似文献
214.
Engineering line diagram development from process flowsheets: Part 1: Shortfalls in current practice
S. Long P. D. B. Bujac D. C. Woodcock M. L. Preston A. G. Rushton I. W. Cumming 《Journal of Loss Prevention in the Process Industries》2000,13(6):459-465
Engineering line diagram (ELD) development forms a distinct phase in process plant design. It is a complex and expensive activity and as such warrants considerable effort to minimise costs and maximise effectiveness. In this paper, the nature of the ELD design task is analysed in order to understand how it could be carried out more effectively. A number of shortfalls in current practice are discussed. These shortfalls were identified through a combination of the following activities: a review of the literature; a survey of current practice and follow-up line diagram development exercise; and task analysis work carried out at ICI. The most significant findings of the survey of current practice are presented. It is proposed that the shortfalls identified can be overcome by introducing structure to the design task. The manner in which this can be achieved is the subject of the second part of this paper. 相似文献
215.
潘奋 《中国安全科学学报》2000,10(5):9-12
阐述安全工程学的基本内容和“安全第一 ,预防为主”的方针。针对当前企业安全生产所面临的道德、心理、安全系统、责任制、监督监察及培训教育等问题 ,探讨了安全工程学与法学、经济学的关系 ,阐明了笔者的观点和研究的思路。 相似文献
216.
罗善明 《中国安全科学学报》2001,11(6):66-68
对有限空间中的淹没非自由射流流压力场的数值解法进行了较为详细的研究和分析 ,并建立了相应的流场力学模型和压力解的第二类边界条件 ,给出了流场的矩形网格几何和边界标记。文中指出 ,精确的压力解只能从泊松形式的压力方程得到 ,且与边界相邻的点和内点应分别采用不同的方程进行求解 相似文献
217.
218.
219.
220.
为了给工程实际应用提供科学依据,文章以煤渣、页岩陶粒、砾石、砂子为吸附剂,以苯、1,4-二氯苯、硝基苯和邻苯二甲酸二丁酯4种有机化合物为吸附质,考察了人工湿地基质对混合溶液中有机化合物的等温吸附行为。结果表明,供试基质对目标有机化合物的吸附等温线均属于Langmuir型;Freundlich方程比Langmuir方程能够更好地拟合实验结果;Langmuir方程的不同线性变换在数据拟合时表现出很大的差异性;供试基质对有机化合物的吸附具有明显的选择性,最好用混合基质来构建以去除有机化合物为目的的人工湿地。 相似文献