全文获取类型
收费全文 | 3576篇 |
免费 | 578篇 |
国内免费 | 1432篇 |
专业分类
安全科学 | 595篇 |
废物处理 | 106篇 |
环保管理 | 291篇 |
综合类 | 2996篇 |
基础理论 | 541篇 |
污染及防治 | 399篇 |
评价与监测 | 248篇 |
社会与环境 | 217篇 |
灾害及防治 | 193篇 |
出版年
2024年 | 44篇 |
2023年 | 96篇 |
2022年 | 261篇 |
2021年 | 275篇 |
2020年 | 335篇 |
2019年 | 207篇 |
2018年 | 192篇 |
2017年 | 210篇 |
2016年 | 231篇 |
2015年 | 242篇 |
2014年 | 268篇 |
2013年 | 299篇 |
2012年 | 378篇 |
2011年 | 329篇 |
2010年 | 307篇 |
2009年 | 283篇 |
2008年 | 269篇 |
2007年 | 278篇 |
2006年 | 265篇 |
2005年 | 183篇 |
2004年 | 144篇 |
2003年 | 93篇 |
2002年 | 82篇 |
2001年 | 99篇 |
2000年 | 55篇 |
1999年 | 48篇 |
1998年 | 18篇 |
1997年 | 21篇 |
1996年 | 15篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 17篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1984年 | 1篇 |
排序方式: 共有5586条查询结果,搜索用时 187 毫秒
541.
本文提出了一套适合于我国中小城市大气污染总量控制研究的技术路线和模型。通过环境容量规划和污染综合治理规划的有机结合,从而达到以优化的方式协调经济发展与环境保护的矛盾。对镇江市的应用结果表明,本文提出的技术路线和模型是合理可行的。所给出的总量控制方案既能符合经济发展的需要,又能经济有效地控制并改善区域的大气环境质量。 相似文献
542.
Because the particulate organic carbon (OC) concentrations reported in U.S. Environment Protection Agency Speciation Trends Network (STN) data were not blank corrected, the OC blank concentrations were estimated using the intercept in particulate matter < or = 2.5 microm in aerodynamic diameter (PM2.5) regression against OC concentrations. The estimated OC blank concentrations ranged from 1 to 2.4 microg/m3 showing higher values in urban areas for the 13 monitoring sites in the northeastern United States. In the STN data, several different samplers and analyzers are used, and various instruments show different method detection limit (MDL) values, as well as errors. A comprehensive set of error structures that would be used for numerous source apportionment studies of STN data was estimated by comparing a limited set of measured concentrations and their associated uncertainties. To examine the estimated error structures and investigate the appropriate MDL values, PM2.5 samples collected at a STN site in Burlington, VT, were analyzed through the application of the positive matrix factorization. A total of 323 samples that were collected between December 2000 and December 2003 and 49 species based on several variable selection criteria were used, and eight sources were successfully identified in this study with the estimated error structures and min values among different MDL values from the five instruments: secondary sulfate aerosol (41%), secondary nitrate aerosol (20%), airborne soil (15%), gasoline vehicle emissions (7%), diesel emissions (7%), aged sea salt (4%), copper smelting (3%), and ferrous smelting (2%). Time series plots of contributions from airborne soil indicate that the highly elevated impacts from this source were likely caused primarily by dust storms. 相似文献
543.
544.
秸秆固定化石油降解菌降解原油的初步研究 总被引:1,自引:0,他引:1
用秸秆做载体固定嗜碱芽孢杆菌(Bacillus alcalophilus SG)降解原油,其原油去除率为73.88%,高于单纯投加菌液或者菌液与秸秆的混合物的原油去除率.秸秆的最佳投加量(干重)为25.0 g/L,最佳固定化时间为30 h.用预处理过的秸秆固定SG,降低了固定化SG的原油去除率.在固定化培养基中添加无机盐离子,促进了固定化SG对原油的降解.不同初始pH的原油培养基在固定化SG降解原油的过程中逐渐呈中性或偏碱性.固定化SG在pH 6.0~10.0时对原油均有不错的降粘能力. 相似文献
545.
546.
分别采用7-乙氧基异酚恶唑酮.脱乙基酶(EROD)活性测定法,重组人激素受体基因的酵母测试和Q67发光菌试验方法,对北京市某生活污水处理厂的进水、二沉出水以及经过石灰法深度处理后的出水中的类二恶英物质、类雌激素物质和急性毒性物质进行了分析。进水中的三类生物毒性效应物质中的急性毒性物质,可通过活性污泥法基本去除,而对类雌激素物质和类二恶英物质的去除率分别为76%和52%。经过石灰沉淀法的深度处理后,可使上述两类物质的总去除率达到95%和68%。出水中的雌激素当量水平与欧洲国家污水处理厂出水水平相当,而类二恶英物质的总浓度低于美国EPA饮用水中二恶英的最大允许浓度。展示了生物毒性测试方法在排水生态风险和工艺评价方面的应用潜力。 相似文献
547.
针对我国污水处理厂分散生产运行管理,污水处理厂自动化、信息化管理水平偏低,有待采用计算机技术、自动控制技术、通信等新技术改进提高,实现污水处理厂远程集中监测、监控问题,提出污水处理厂远程监测、监控系统开发参考模型。阐述了污水处理厂远程监控系统的结构体系、开发思路、污水处理厂现场控制对象及设计、监控中心设计、监控中心和各污水处理厂通信设计、开发工具及监控软件设计等技术及要求。 相似文献
548.
549.
膨润土对Pb2+、Cu2+、Cr3+的吸附动力学及等温线研究 总被引:1,自引:0,他引:1
研究所用膨润土的主要成分为SiO2和Al2O3,属于Ca基膨润土,BET表面积为50.83 m2/g.在恒温及恒定pH条件下,用静态吸附法研究了膨润土对Pb2 、Cu2 、Cr3 的吸附特性,结果表明其较好地符合Lagergten二级吸附速率方程,对这3种离子的吸附速率为Pb2 >Cu2 >Cr3 .利用3种等温线方程对吸附过程进行拟合,发现利用Langmuir吸附等温方程计算的值与膨润土吸附Pb2 、Cu2 、Cr3 试验数据最为吻合.膨润土对3种金属离子的平衡吸附量为Cr3 >Cu2 >Pb2 . 相似文献
550.
Yanyan Qin Xinghua Hu Zhaoyi He Shuqing Li 《Journal of the Air & Waste Management Association (1995)》2020,70(7):670-686
ABSTRACT
Cooperative adaptive cruise control (CACC) vehicles need vehicle-to-vehicle (V2 V) communication to achieve CACC function. When a CACC vehicle follows a manual-driven vehicle (MDV) without V2 V communication, it needs degenerate to adaptive cruise control (ACC). By using real experiments, California PATH program indicated that ACC vehicles are apt to be unstable, which may have negative influence on fuel consumption and traffic emissions. Hence, this paper studies the impacts of the mixed CACC-MDV traffic on fuel consumption and emissions, by taking into consideration partial degenerations from stable CACC vehicles to unstable ACC vehicles. To deal with this, microscopic simulations were adopted by using car-following models. Then, an appropriate emission model was used for evaluating the emission impacts under different CACC market penetration rates (MPRs). In order to obtain reliable evaluation results, the models validated by PATH program using real experimental data were employed as the CACC and ACC car-following models. In addition, we also analytically investigated stability of the mixed traffic flow under different CACC MPRs, in order to explore its relationship with the emission impacts. The results show that the fuel consumption and emissions firstly increase and then decrease with the increase of the CACC MPR. This means the mixed traffic under some ranges of CACC MPRs will produce more fuel consumption and emissions, compared with the full MDVs traffic. It indicates that stability situations of the mixed traffic qualitatively influence the impact trend of CACC MPRs on fuel consumption and emissions. Then, V2 V communication equipments on MDVs are not only encouraging but also essential to avoid the deterioration of fuel consumption and emissions of the mixed traffic flow. 相似文献