全文获取类型
收费全文 | 5469篇 |
免费 | 125篇 |
国内免费 | 904篇 |
专业分类
安全科学 | 262篇 |
废物处理 | 326篇 |
环保管理 | 448篇 |
综合类 | 1790篇 |
基础理论 | 1145篇 |
环境理论 | 2篇 |
污染及防治 | 1796篇 |
评价与监测 | 316篇 |
社会与环境 | 242篇 |
灾害及防治 | 171篇 |
出版年
2023年 | 58篇 |
2022年 | 184篇 |
2021年 | 141篇 |
2020年 | 83篇 |
2019年 | 105篇 |
2018年 | 187篇 |
2017年 | 152篇 |
2016年 | 186篇 |
2015年 | 224篇 |
2014年 | 245篇 |
2013年 | 484篇 |
2012年 | 263篇 |
2011年 | 343篇 |
2010年 | 282篇 |
2009年 | 271篇 |
2008年 | 305篇 |
2007年 | 303篇 |
2006年 | 241篇 |
2005年 | 193篇 |
2004年 | 203篇 |
2003年 | 212篇 |
2002年 | 175篇 |
2001年 | 291篇 |
2000年 | 201篇 |
1999年 | 149篇 |
1998年 | 101篇 |
1997年 | 103篇 |
1996年 | 82篇 |
1995年 | 88篇 |
1994年 | 69篇 |
1993年 | 78篇 |
1992年 | 60篇 |
1991年 | 59篇 |
1990年 | 41篇 |
1989年 | 35篇 |
1988年 | 25篇 |
1987年 | 18篇 |
1986年 | 18篇 |
1985年 | 15篇 |
1984年 | 21篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 18篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1975年 | 12篇 |
1973年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有6498条查询结果,搜索用时 15 毫秒
121.
122.
J. Y. Kim M.-C. Shin J.-R. Park K. Nam 《Journal of Material Cycles and Waste Management》2003,5(1):0055-0062
The effect of the soil solids concentration in batch tests on the measured values of the partition coefficient (K
p) of organic pollutants in landfill liner-soil material was investigated. Since this study was based on the results of batch
and column tests conducted independently, there were limitations to the conclusions derived. The organic compounds tested
were benzene, methylene chloride, toluene, trichloroethylene, and p-xylene. The results of this study showed that as soil solids concentrations increased, the measured K
p values of these organic compounds strongly decreased. The observed values of K
p stabilized when the soil solids concentration was above a certain value. Typical K
p values obtained from batch tests conducted under high soil solids concentrations were close to those obtained from column
tests. It was concluded that the K
p values of organic compounds measured under low soil solids concentrations, i.e., less than 100 g/l, may not correctly simulate
the field situation. Consequently, the values of K
p obtained with low soil solids concentrations can result in an overestimation of the retardation factor of the landfill liner
material.
Received: March 14, 2002 / Accepted: August 25, 2002 相似文献
123.
124.
本文对伽师成丛发生强震的机因,伽师地震的预报以及地震灾害损失与应力场状态等给出了结果。并就伽师地区防震减灾对策和重建问题提出了讨论及具体对策意见。 相似文献
125.
Summary Pesticide residues in soil, water, food, wildlife and other media have been analysed in several monitoring studies. The purpose was to establish the distribution of these residues across a defined area, ascertain their trend over a specific period and use the results to assess environmental compliance and safety. In the present review the availability of information on pesticide residues in various Canadian environmental components was sought. With the possible exception of localized pesticide contamination of some private water supply wells, ground and surface water, most analyses revealed concentrations below guideline limits. Only a few cases were reported of mishandling, misuse and poisoning from pesticides. Continuing surveillance programmes and in-depth and well-organized monitoring studies, with special focus on areas that are vulnerable to contamination, by both provincial and federal governments, are largely responsible for the encouraging results. This experience in the control of pesticide use and monitoring of residues in the environment should be of particular interest in developing countries.Dr A.Y. Sangodoyin is a senior lecturer in the Department of Agricultural Engineering at the University of Ibadan. He was recently involved in a study visit to the University of Alberta, Edmonton, Alberta, Canada T6G 2G7, where his co-author Dr D.W. Smith is a member of staff in the Department of Civil-Engineering. 相似文献
126.
127.
128.
129.
Jonn A. Foulk Wayne Y. Chao Danny E. Akin Roy B. Dodd Patricia A. Layton 《Journal of Polymers and the Environment》2004,12(3):165-171
Municipal solid wastes generated each year contain potentially useful and recyclable materials for composites. Simultaneously, interest is high for the use of natural fibers, such as flax (Linum usitatissimum L.), in composites thus providing cost and environmental benefits. To investigate the utility of these materials, composites containing flax fibers with recycled high density polyethylene (HDPE) were created and compared with similar products made with wood pulp, glass, and carbon fibers. Flax was either enzyme- or dew-retted to observe composite property differences between diverse levels of enzyme formulations and retting techniques. Coupling agents would strengthen binding between fibers and HDPE but in this study fibers were not modified in anyway to observe mechanical property differences between natural fiber composites. Composites with flax fibers from various retting methods, i.e., dew- vs. enzyme-retting, behaved differently; dew-retted fiber composites resulted in both lower strength and percent elongation. The lowest level of enzyme-retting and the most economical process produces composites that do not appear to differ from the highest level of enzyme-retting. Flax fibers improved the modulus of elasticity over wood pulp and HDPE alone and were less dense than glass or carbon fiber composites. Likely, differences in surface properties of the various flax fibers, while poorly defined and requiring further research, caused various interactions with the resin that influenced composite properties. 相似文献
130.
随着我国油田相继进入开发后期,传统的滤料及设备过滤精度已不能满足注水的要求。因此,研究并开发了具有一定抗油污能力的新型过滤材料,设计了新型的超精细过滤器系列产品。对滤料进行的室内实验结果表明,在开始过滤的近10h内,过滤后的水中含油量基本上满足注水的水质要求。在开始过滤的近20h内,滤层的水头损失随时间的变化较为平缓;随着过滤时间的延长,水头损失变化加剧。从现场实验可以看出,所设计的过滤器有良好的过滤性能和抗冲击能力。新型过滤材料的研究成功解决了油田含油污水精细过滤的问题,新型过滤器也是含油污水超精细过滤的理想产品。 相似文献