全文获取类型
收费全文 | 1634篇 |
免费 | 157篇 |
国内免费 | 728篇 |
专业分类
安全科学 | 164篇 |
废物处理 | 98篇 |
环保管理 | 163篇 |
综合类 | 1142篇 |
基础理论 | 236篇 |
污染及防治 | 521篇 |
评价与监测 | 79篇 |
社会与环境 | 61篇 |
灾害及防治 | 55篇 |
出版年
2024年 | 6篇 |
2023年 | 57篇 |
2022年 | 113篇 |
2021年 | 114篇 |
2020年 | 100篇 |
2019年 | 72篇 |
2018年 | 79篇 |
2017年 | 99篇 |
2016年 | 88篇 |
2015年 | 107篇 |
2014年 | 143篇 |
2013年 | 195篇 |
2012年 | 133篇 |
2011年 | 159篇 |
2010年 | 124篇 |
2009年 | 101篇 |
2008年 | 103篇 |
2007年 | 91篇 |
2006年 | 88篇 |
2005年 | 62篇 |
2004年 | 42篇 |
2003年 | 38篇 |
2002年 | 45篇 |
2001年 | 44篇 |
2000年 | 50篇 |
1999年 | 44篇 |
1998年 | 41篇 |
1997年 | 31篇 |
1996年 | 35篇 |
1995年 | 32篇 |
1994年 | 18篇 |
1993年 | 13篇 |
1992年 | 17篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1974年 | 1篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有2519条查询结果,搜索用时 15 毫秒
201.
S. H. Lin L. T. Fan C. L. Hwang 《Journal of the American Water Resources Association》1973,9(4):689-702
A modified transient version of the Streeter-Phelps model along with the energy balance equation is employed to analyze the effects of waste heat discharge from power plants on stream water quality. Analysis is also made to examine the effects of the upstream water quality and stream velocity on the downstream DO concentration level. The resulting coupled nonlinear hyperbolic partial differential equations representing the energy, BOD and DO concentrations are solved by the method of characteristics and simulated on a digital computer. Final numerical results indicate that the allowable quantity of thermal discharge does heavily depend on the upstream quality. 相似文献
202.
S. H. Lin L. T. Fan C. L. Hwang 《Journal of the American Water Resources Association》1973,9(5):874-883
ABSTRACT: The purpose of this work is to study the installation of artificial aerators for water quality control of a stream which receives thermal and organic waste discharges. The location and numer of diffuser type aerators to be installed along the stream are determined so as to maintain the stream DO content above a certain minimum requirement (4 mg/l or 5 mg/l) for normal aquatic life. Effects of the stream velocity, upstream BOD concentration and rates of thermal and organic waste discharges to the stream are examined. 相似文献
203.
虚拟现实技术在安全工程中的应用 总被引:23,自引:2,他引:21
论述了虚拟现实技术(VirtualReality)的基本原理、应用范围。结合大空间公用建筑火灾虚拟现实系统,提出了安全工程中应用虚拟现实技术的基本结构及程序设计关键技术,给出了大空间公用建筑火灾虚拟现实系统编制实例 相似文献
204.
Grulke NE Preisler HK Fan CC Retzlaff WA 《Environmental pollution (Barking, Essex : 1987)》2002,119(2):163-175
In highly polluted sites, stomatal behavior is sluggish with respect to light, vapor pressure deficit, and internal CO2 concentration (Ci) and poorly described by existing models. Statistical models were developed to estimate stomatal conductance (gs) of 40-year-old ponderosa pine at three sites differing in pollutant exposure for the purpose of calculating O3 uptake. Gs was estimated using julian day, hour of day, pre-dawn xylem potential and photosynthetic photon flux density (PPFD). The median difference between estimated and observed field gs did not exceed 10 mmol H2O m(-2) s(-1), and estimated gs within 95% confidence intervals. 03 uptake was calculated from hourly estimated gs, hourly O3 concentration, and a constant to correct for the difference in diffusivity between water vapor and 03. The simulation model TREGRO was also used to calculate the cumulative 03 uptake at all three sites. 03 uptake estimated by the statistical model was higher than that simulated by TREGRO because gas exchange rates were proportionally higher. O3 exposure and uptake were significantly correlated (r2>0.92), because O3 exposure and gs were highly correlated in both statistical and simulation models. 相似文献
205.
206.
我国城市生活垃圾的处理和发展趋势 总被引:6,自引:0,他引:6
城市生活垃圾给城市环境造成了严重污染,威胁了城市居民的生存环境和经济、社会的可持续发展。目前,国内采取的垃圾处理技术主要有卫生填埋、焚烧、堆肥等,热解技术由于具有资源回收率高、二次污染小、综合效益好等优点,越来越适合我国中小城市的垃圾处理。垃圾气化技术的研究成为当今世界的热点。此外,我国对垃圾衍生燃料的研究也刚刚起步。为促进城市持续、稳定的发展,提出了垃圾分类收集、分拣、综合利用垃圾处理技术的措施。 相似文献
207.
208.
选择性吸附-高效生物降解法处理含硝基苯与苯酚混合废水 总被引:1,自引:0,他引:1
结合NDA-150型树脂(简称树脂)选择性吸附和生物降解的优点,对含硝基苯和苯酚的模拟混合废水(简称混合废水)进行处理。通过树脂的选择性吸附,使混合废水中的硝基苯和苯酚分离,随后用高效菌对树脂所吸附的硝基苯进行生物降解,同时实现树脂的再生。实验结果表明:通过调节混合废水的pH,树脂可有效地将混合废水中的硝基苯和苯酚进行选择性吸附分离;树脂对硝基苯的吸附是可逆的;树脂的再生程度受微生物对可利用硝基苯质量浓度的下限(1.2mg/L)限制;吸附-生物再生循环实验结果表明,该树脂可有效抵抗微生物的生物降解与破坏。 相似文献
209.
针对我国现行的民航灾害应急联动救援体系所存在着多头指挥、组织形式不明确、责任关系不协调、信息沟通不顺畅、资源调度不合理等问题,运用文献检索、理论分析与实地调研相结合的方法,笔者提出优化思路:民航灾害应急联动机制应以各级民航管理当局的飞行事故应急指挥部为主要指挥决策者,采用虚拟的网络式组织形式,理顺联动单位的责任与关系,将应急联动的信息网络与各地突发公共危机事件的信息平台接轨,成立全国统一的、具有双重功能的民航灾害应急资源调度中心。其中,对民航灾害应急联动虚拟网络组织形式的设计,较好地改进了现行组织的效率,体现了快速反应和协调行动的要求。 相似文献
210.
Zhisheng Zhang Guenter Engling Chuan-Yao Lin Charles C.-K. Chou Shih-Chun C. Lung Shih-Yu Chang Shaojia Fan Chuen-Yu Chan Yuan-Hang Zhang 《Atmospheric environment (Oxford, England : 1994)》2010,44(26):3187-3195
Intensive measurements of aerosol (PM10) and associated water-soluble ionic and carbonaceous species were conducted in Guangzhou, a mega city of China, during summer 2006. Elevated levels of most chemical species were observed especially at nighttime during two episodes, characterized by dramatic build-up of the biomass burning tracers levoglucosan and non-sea-salt potassium, when the prevailing wind direction had changed due to two approaching tropical cyclones. High-resolution air mass back trajectories based on the MM5 model revealed that air masses with high concentrations of levoglucosan (43–473 ng m?3) and non-sea-salt potassium (0.83–3.2 μg m?3) had passed over rural regions of the Pearl River Delta and Guangdong Province, where agricultural activities and field burning of crop residues are common practices. The relative contributions of biomass burning smoke to organic carbon in PM10 were estimated from levoglucosan data to be on average 7.0 and 14% at daytime and nighttime, respectively, with maxima of 9.7 and 32% during the episodic transport events, indicating that biomass and biofuel burning activities in the rural parts of the Pearl River Delta and neighboring regions could have a significant impact on ambient urban aerosol levels. 相似文献