全文获取类型
收费全文 | 528篇 |
免费 | 1篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 12篇 |
环保管理 | 32篇 |
综合类 | 306篇 |
基础理论 | 80篇 |
环境理论 | 1篇 |
污染及防治 | 80篇 |
评价与监测 | 9篇 |
社会与环境 | 5篇 |
出版年
2021年 | 5篇 |
2013年 | 13篇 |
2012年 | 17篇 |
2011年 | 10篇 |
2010年 | 10篇 |
2009年 | 9篇 |
2008年 | 9篇 |
2007年 | 15篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 13篇 |
2000年 | 18篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1990年 | 11篇 |
1984年 | 5篇 |
1975年 | 5篇 |
1969年 | 6篇 |
1968年 | 6篇 |
1966年 | 6篇 |
1965年 | 6篇 |
1964年 | 6篇 |
1963年 | 9篇 |
1962年 | 6篇 |
1961年 | 11篇 |
1960年 | 13篇 |
1959年 | 9篇 |
1958年 | 13篇 |
1957年 | 8篇 |
1955年 | 11篇 |
1954年 | 6篇 |
1943年 | 5篇 |
1941年 | 5篇 |
1938年 | 5篇 |
1937年 | 4篇 |
1935年 | 4篇 |
1934年 | 4篇 |
1928年 | 5篇 |
1923年 | 6篇 |
1919年 | 5篇 |
1914年 | 6篇 |
1913年 | 5篇 |
排序方式: 共有535条查询结果,搜索用时 15 毫秒
191.
192.
193.
194.
There is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two-dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real-time concentration measurement. Gas distribution in the soil profile was sampled with gas-tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed-furrow system. A 5-h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3-bromo-1-propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br-) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration-time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models. 相似文献
195.
The gas permeability of plastic films is important in packaging, containment, and agricultural fumigation. Recently, an approach for estimating the mass transfer coefficient of vapors across a film was presented by Papiernik et al. (2001). The mass transfer coefficient is an intrinsic property of a film-chemical combination, independent of the concentration gradient maintained across the film. Here we describe an apparatus useful for obtaining permeability data; the model of Papiernik et al. (2001) may be fitted to the data to determine mass transfer coefficients. The assembled equipment provides a sealed permeability cell, where a sample of the film to be tested is sandwiched between two static half-cells. Vapor is spiked to one side of the film and the concentrations in the spiked and receiving chamber are monitored until equilibrium. A sealed system is required for this approach; the permeability cells described here were gas-tight for >40 d. This approach produces reproducible measures of mass transfer coefficients that are not dependent on the size of the experimental apparatus. Model parameters were similar when fitted simultaneously as when determined independently from the same data set. 相似文献
196.
Evidence suggesting that job satisfaction is caused by individual dispositions is reviewed, and stability coefficients for job satisfaction in previous studies are analysed with a meta‐analytic procedure. Previous longitudinal studies analysing job changer samples imply an upper limit estimate of 0.51 for direct dispositional influences on job satisfaction. A study of job changers considering the stability of working conditions suggests that this estimate has to be considerably corrected downwards. At present, it is concluded that it is more likely that dispositions indirectly affect job satisfaction via selection and self‐selection processes. Implications for job satisfaction as a tool for organizational assessment are discussed. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
197.
Urs Baumann Gustav Peter Ernst Pletscher Marcel Wettstein 《Environmental Sciences Europe》2003,15(4):227-233
Before waste-water-relevant organic materials are to be found in large quantities, their specific behavior in sewage treatment plants must be known. With the aid of the OECD simulation test #303 A, an estimation of their elimination in biological clarification stages can be made. In this work, an economical and continuous testing system is presented, which consists of a polyester flies bound to an activated biosludge with a high inoculum density, allowing one to measure no only the elimination of individual substances, but also the specific degree of mineralization. The toxicity of the activated biosludge and the nitrifying substances can also be examined. With the described testing procedure, it is possible to determine the rate of degradation within only a few hours. Finally, it can also be seen that it is possible to reliably and continuously determine the rate of anaerobic, biological degradability through the use of such a modified testing procedure. 相似文献
198.
199.
200.
A growing awareness of increasing trends in coastal erosion and flooding due to climate change is triggering a demand for the rapid assessment of the potential responses of the coastlines around the world, principally in locations where human occupation is especially endangered. Investigations of present and future physical vulnerability and associated social risk have, therefore, become crucial for coastal management. In order to provide a quick and simple methodology for the identification of vulnerable coastal segments, Sharples (2006) has proposed a mapping methodology, called the smartline approach, which consists of representing, by means of simple lines, a geomorphic classification of the hinterland, backshore and beaches. The aim of this paper is to apply the smartline approach to coastal vulnerability assessment with inclusion of social data. The results show that this methodology is appropriate for the indication of coastal segments with varying degrees of vulnerability to erosion and flooding and for the appraisal of the resulting social risk. 相似文献