全文获取类型
收费全文 | 475篇 |
免费 | 29篇 |
国内免费 | 10篇 |
专业分类
安全科学 | 177篇 |
废物处理 | 2篇 |
环保管理 | 71篇 |
综合类 | 108篇 |
基础理论 | 65篇 |
污染及防治 | 12篇 |
评价与监测 | 26篇 |
社会与环境 | 38篇 |
灾害及防治 | 15篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 6篇 |
2019年 | 17篇 |
2018年 | 8篇 |
2017年 | 14篇 |
2016年 | 15篇 |
2015年 | 17篇 |
2014年 | 17篇 |
2013年 | 48篇 |
2012年 | 27篇 |
2011年 | 38篇 |
2010年 | 20篇 |
2009年 | 22篇 |
2008年 | 21篇 |
2007年 | 25篇 |
2006年 | 32篇 |
2005年 | 27篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 14篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有514条查询结果,搜索用时 15 毫秒
31.
Management by objectives (MBO) is a technique for integrating ecological concerns into national political and administrative
structures. Politicians determine environmental objectives and interim targets to be implemented and assessed by civil servants
in national, regional, and local contexts. Well-developed organizational communication is a prerequisite for MBO. However,
communication-related obstacles can arise when using MBO in public environmental management. We examine communicative aspects
of environmental MBO, looking specifically at the implementation, administration, and assessment of Swedish environmental
quality objectives. Our argument is illustrated by quotations from individual and focus group interviews. We conclude that
communicative problems may arise, because different actors interpret messages from different perspectives, depending on their
agendas, prior knowledge and experience, and positions in the administrative system. It is crucial to recognize the dialogical
aspects of communication, by involving the receiver of a message in a process of response. In addition, the different timeframes
underlying different arguments could contribute to misunderstandings between actors involved in handling environmental issues.
In assessing the achievement of environmental objectives, indicators are used as communicative tools. It is important to investigate
whether and how these indicators contribute to the de- and recontextualization of environmental objectives. 相似文献
32.
为了研究平行双样对天然气中硫化物采样质量控制措施的可靠性,对现场采集的8对硫化物平行样用对氨基二甲基苯胺光度法进行测定。对测定结果及相对偏差进行W(Shapiro-Wilk)检验,检验结果说明平行双样相对偏差服从正态分布,数据的一致性较好,说明用平行双样对采样进行质量控制是可行的。文中还用Grubbs检验法计算出在该实验条件下测定天然气中硫化物平行双样的相对偏差质量控制范围为1.93%±12.5%。 相似文献
33.
用分光光度法测定水中化学需氧量CODCr,通过正交试验选择氧化的最佳选择。试验结果表明对CODCr值为50~1000mg/L的水样:氧化剂K2Cr2O7用量为0.20~0.40mol/L,催化剂Ag2SO4用量为10g/LH2SO4,消解时间10min,加热温度180℃。用CODCr为138mg/L的质控标样进行验证试验,其绝对误差为0.5~3.0mg/L。与标准方法相比用分光光度法测定CODCr具有分析误差小,省时、省力,节约药剂的特点。 相似文献
34.
35.
针对间歇式加煤锅炉在烟尘实际测试中,最终测试结果容易出现误差的问题,通过试验,分析造成误差的主要原因和规律,提出了消除和减小误差的相应对策 相似文献
36.
ABSTRACT: A linear filter (Kalman filter) technique was used with a Streamflow-concentration model the minimize surface water quality sampling frequencies when determining annual mean solute concentrations with a predetermined allowable error. The Kalman filter technique used the stream discharge interval as a replacement for the more commonly used time interval. Using filter computations, the measurement error variance was minimized within the sample size constraints. The Kalman filter application proposed here is applicable only under several conditions including: monitoring is solely to estimate annual mean concentration; discharge measurement errors are negligible; the Streamflow-concentration model is valid; and monthly samples reflect the total variance of the solute in question. 相似文献
37.
Kristin Bunte Steven R. Abt 《Journal of the American Water Resources Association》2001,37(4):1001-1014
ABSTRACT: Improved sampling techniques are needed to increase the accuracy of pebble‐count particle‐size distributions used for stream studies in gravel‐bed streams. However, pebble counts are prone to operator errors introduced through subjective particle selection, serial correlation, and inaccurate particle‐size measurements. Errors in particle‐size measurements can be minimized by using a gravel template. Operator influence on particle selection can be minimized by using a sampling frame, 60 by 60 cm, in which sampling points are identified by the cross points of thin elastic bands. Serial correlation can be minimized by adjusting the spacing between the cross points and setting it equal to the dominant large particle size (=D95). In a field test in a cobble‐bed stream, the sampling frame developed in this study produced slightly coarser size distributions, particularly in the cobble range, than the traditional heel‐to‐toe walk that selects particles with a blind touch at the tip of the boot. The sampling frame produced more similar sampling results between two operators than heel‐to‐toe walks. The difference between the two sampling methods is attributed to an unbiased selection of fine and coarse particles when using the sampling frame. 相似文献
38.
Tam CL 《Environmental management》2006,38(1):1-15
Participatory environmental and resource management is premised on open communication to reach consensus. However, deliberate and open communication cannot adequately address silent conflict. This begs two questions. First, how is the existence of covert communication and silent conflict to be recognized and addressed? Second, how are the wider social relations and traditions that encompass communication and conflict to be described and explained? These questions revolve around communicative power. Communication of environmental knowledge is deeply embedded in social power structures, with direct implications for participatory resource planning and implementation. Ethnographic research conducted at a failed community-managed fish farming project in Southeast Sulawesi, Indonesia shows that a culture of harmony and respect for authority can silence environmental conflict in the hierarchical “community.” Three propositions are offered. First, communication amnesia and exclusion jeopardize participation. Second, cultures of harmony and silent conflict shape planning processes and outcomes. Third, the weak use manipulation and communication strategy to acquire a “voice” while preserving harmony. These propositions address five unresolved issues in participatory resource management: analysis of groups, contextuality, social relationships, nonparticipants, and informal communication. Power, tradition, and social networks affect the valuing of knowledge relative to the power of different individuals and institutions to communicate priorities, values, and needs. These factors are critical to the inclusion of both participants and nonparticipants. 相似文献
39.
40.
旋转压缩机油路系统仿真与试验研究 总被引:1,自引:0,他引:1
压缩机泵油系统对滚动转子压缩机性能和可靠性非常重要.为了了解压缩机泵油特性.本文应用CFD软件,采用VOF模型对滚动转子压缩机整个泵油系统进行数值模拟,搭建试验台进行试验,并将模拟和试验结果进行对比,结果表明上法兰螺旋槽处润滑油流量结果吻合很好,误差在10%以内,证明了该仿真方法的可行性. 相似文献