全文获取类型
收费全文 | 2442篇 |
免费 | 131篇 |
国内免费 | 659篇 |
专业分类
安全科学 | 160篇 |
废物处理 | 186篇 |
环保管理 | 245篇 |
综合类 | 1110篇 |
基础理论 | 443篇 |
环境理论 | 2篇 |
污染及防治 | 720篇 |
评价与监测 | 179篇 |
社会与环境 | 102篇 |
灾害及防治 | 85篇 |
出版年
2024年 | 8篇 |
2023年 | 46篇 |
2022年 | 105篇 |
2021年 | 101篇 |
2020年 | 96篇 |
2019年 | 83篇 |
2018年 | 100篇 |
2017年 | 116篇 |
2016年 | 116篇 |
2015年 | 112篇 |
2014年 | 152篇 |
2013年 | 204篇 |
2012年 | 178篇 |
2011年 | 180篇 |
2010年 | 169篇 |
2009年 | 182篇 |
2008年 | 188篇 |
2007年 | 161篇 |
2006年 | 155篇 |
2005年 | 92篇 |
2004年 | 93篇 |
2003年 | 75篇 |
2002年 | 71篇 |
2001年 | 62篇 |
2000年 | 64篇 |
1999年 | 58篇 |
1998年 | 35篇 |
1997年 | 22篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有3232条查询结果,搜索用时 125 毫秒
791.
纪欣 《石油化工环境保护》2006,29(2):34-36
对炼油、化工废水治理生产实践进行研究与探讨,提出应对高浓度混合污水的处理方法,对各种影响治理的因素有针对性地采取应对措施,提高了污水处理抗冲击能力和治理效果,对实现长周期平稳运行具有积极意义。 相似文献
792.
A three‐dimensional hydrodynamic model was applied to Lake Paldang, South Korea. The lake has three inflows, of which Kyoungan Stream has the smallest flow rate and poorest water quality. Since all drinking water intake stations are located near the confluence of Kyoungan Stream within the lake, this contaminated tributary may have a significant impact on the quality of drinking water sources. The optimum drinking water intake location was determined from the applied model. The model was calibrated and verified using the data measured under different hydrological conditions. The model results were in reasonable agreement with the field measurements in both calibration and verification. The circulation and spreading patterns of the incoming flows in the lake, as well as their composition ratios to the drinking water intakes were determined from the model, and three alternative intake locations were proposed. The simulation results suggested that the horizontal and vertical relocations of the intake aqueduct could significantly decrease the composition ratio of the contaminated water. From this study, it was concluded that the three‐dimensional hydrodynamic model could successfully simulate the temporal and spatial mixing patterns of incoming flows and become a useful tool in determining the optimum water intake location in Lake Paldang. 相似文献
793.
A. Allen Bradley Christa Peters‐Lidard Brian R. Nelson James A. Smith C. Bryan Young 《Journal of the American Water Resources Association》2002,38(5):1393-1407
ABSTRACT: A general framework is proposed for using precipitation estimates from NEXRAD weather radars in raingage network design. NEXRAD precipitation products are used to represent space time rainfall fields, which can be sampled by hypothetical raingage networks. A stochastic model is used to simulate gage observations based on the areal average precipitation for radar grid cells. The stochastic model accounts for subgrid variability of precipitation within the cell and gage measurement errors. The approach is ideally suited to raingage network design in regions with strong climatic variations in rainfall where conventional methods are sometimes lacking. A case study example involving the estimation of areal average precipitation for catchments in the Catskill Mountains illustrates the approach. The case study shows how the simulation approach can be used to quantify the effects of gage density, basin size, spatial variation of precipitation, and gage measurement error, on network estimates of areal average precipitation. Although the quality of NEXRAD precipitation products imposes limitations on their use in network design, weather radars can provide valuable information for empirical assessment of rain‐gage network estimation errors. Still, the biggest challenge in quantifying estimation errors is understanding subgrid spatial variability. The results from the case study show that the spatial correlation of precipitation at subgrid scales (4 km and less) is difficult to quantify, especially for short sampling durations. Network estimation errors for hourly precipitation are extremely sensitive to the uncertainty in subgrid spatial variability, although for storm total accumulation, they are much less sensitive. 相似文献
794.
Water, Air, &; Soil Pollution: Focus - 相似文献
795.
796.
Christopher P. Parker Boris B. Baltes Scott A. Young Joseph W. Huff Robert A. Altmann Heather A. LaCost Joanne E. Roberts 《组织行为杂志》2003,24(4):389-416
In this study, meta‐analytic procedures were used to examine the relationships between individual‐level (psychological) climate perceptions and work outcomes such as employee attitudes, psychological well‐being, motivation, and performance. Our review of the literature generated 121 independent samples in which climate perceptions were measured and analyzed at the individual level. These studies document considerable confusion regarding the constructs of psychological climate, organizational climate, and organizational culture and reveal a need for researchers to use terminology that is consistent with their level of measurement, theory, and analysis. Our meta‐analytic findings indicate that psychological climate, operationalized as individuals' perceptions of their work environment, does have significant relationships with individuals' work attitudes, motivation, and performance. Structural equation modeling analyses of the meta‐analytic correlation matrix indicated that the relationships of psychological climate with employee motivation and performance are fully mediated by employees' work attitudes. We also found that the James and James ( 1989 ) PCg model could be extended to predict the impact of work environment perceptions on employee attitudes, motivation, and performance. Despite the number of published individual‐level climate studies that we found, there is a need for more research using standardized measures so as to enable analyses of the organizational and contextual factors that might moderate the effects of psychological climate perceptions. Finally, we argue for a molar theory of psychological climate that is rooted in the psychological processes by which individuals make meaning or their work experiences. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
797.
798.
Straw bio-degradation by acidogenic bacteria and composite fungi 总被引:2,自引:0,他引:2
A composite microbial system, including a strain of Candida tropicalis (W3), a strain of Lactobacillus plantarm(WY3) and three strains of basidiomycete pL104, pL113 and C33, was chosen to degrade com straw.The final pH was acid owing to the inoculation of acidogenic bacteria, and under this condition the composite fungi system could produce complex enzyme to destroy the compact structure of corn straw. The experimental results showed that the biomass of composite fungi could reach up to maximum when the pH value was 4.5. Through the bio-degradation by combining acidogenic bacteria with the composite fungi system, the cellulose, hemi-ceUulose and lignin degradation rates of corn straw powder were 26.36%, 43.30% and 26.96%, respectively. And the gross crude protein content increased 60.41%. This study provided the evidence for the feasibility of developing a composite microbial system with high capability of degrading straw lignocelluloses in order to make reasonable use of straw resource and protect rural eco-environment. 相似文献
799.
800.
针对油气事故后应急资源需求预测困难的问题,在对油气事故特性及应急资源需求类型分析的基础上,构建了基于案例推理(CBR)的油气事故应急资源需求预测模型,并使用Visual Basic.NET及SQL Server数据库开发了油气事故应急资源需求预测支持决策系统。将该系统应用于实际油气事故案例进行验证,结果表明系统中应急资源需求预测模型科学可靠,系统对油气事故应急资源需求预测结果与其实际用量基本吻合。该系统可为油气事故后快速有效开展应急救援活动提供相应的理论依据。 相似文献