全文获取类型
收费全文 | 91篇 |
免费 | 17篇 |
国内免费 | 29篇 |
专业分类
安全科学 | 24篇 |
废物处理 | 4篇 |
环保管理 | 8篇 |
综合类 | 67篇 |
基础理论 | 14篇 |
污染及防治 | 15篇 |
评价与监测 | 3篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 3篇 |
2013年 | 9篇 |
2012年 | 9篇 |
2011年 | 11篇 |
2010年 | 3篇 |
2009年 | 6篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有137条查询结果,搜索用时 31 毫秒
111.
112.
113.
介绍了数控冲床、数控折弯机、数控激光切割机、数控剪板机等CNC板材加工设备的特点,以及这些先进的设备在钣金加工业中的应用和我国钣金生产的加工技术的发展趋向. 相似文献
114.
OH自由基绝对标定系统的建立和研究 总被引:1,自引:0,他引:1
利用H2 O在 1 85nm紫外光照射下产生定量OH自由基 ,用低压扩散激光诱导荧光技术建立了OH自由基标定系统 .在实验条件下 ,体系产生OH自由基的浓度范围为 3× 1 0 7— 2× 1 0 9个·cm- 3,得到归一化荧光信号 (S)与OH自由基浓度的定量关系为S =6 0 4× 1 0 - 9[OH]- 0 0 4 0 7(R2 =0 987) ,并研究和讨论了饱和效应以及体系中可能存在的干扰 . 相似文献
115.
以脉冲激光为光源、纳米金为催化剂,对2,4,5-三氯苯酚(2,4,5-TCP)进行了光催化降解研究,测定了其反应动力学参数,确定了该降解体系中2,4,5-三氯苯酚的单位能量降解率和平均反应速率.EDX能谱和透射电镜表征结果表明,已成功制备了纳米金颗粒,形态主要呈球状,粒径分布均匀,大小在15~20 nm之间.以亚甲基蓝为底物对纳米金的光催化性能进行了表征,结果表明,所制备的纳米金具有较好的催化性能,添加纳米金组比对照组的亚甲基蓝脱色率增加了约15.7%.以2,4,5-TCP为底物时,脉冲激光照射40 min,最高催化降解率约为85%,单位能量降解率为0.18256%·J-1,平均反应速率为0.04667 min-1,反应符合准一级动力学方程ln(C0/Ct)=-0.1141+0.04667t. 相似文献
116.
Mingqiang Huang Weijun Zhang Xuejun Gu Changjin Hu Weixiong Zhao Zhenya Wang Li Fang 《环境科学学报(英文版)》2012,24(5):860-864
Secondary organic aerosol (SOA) formed from Cl-initiated oxidation of toluene was investigated in a home-made smog chamber. The size distribution and chemical composition of SOA particles were measured using aerodynamic particle sizer spectrometer and the aerosol laser time-of-flight mass spectrometer (ALTOFMS), respectively. According to a large number of single aerosol diameter and mass spectra, the size distribution and chemical composition of SOA were obtained statistically. Experimental results showed that SOA particles created by Cl-initiated oxidation of toluene is predominantly in the form of fine particles, which have diameters less than 2.5 m (i.e., PM2.5), and glyoxal, benzaldehyde, benzyl alcohol, benzoquinone, benzoic acid, benzyl hydroperoxide and benzyl methyl nitrate are the major products components in the SOA. The possible reaction mechanisms leading to these products are also proposed. 相似文献
117.
A new FAGE setup has recently been built at the University of Lille, France. It permits the quantification of OH and HO2 in the atmosphere with a detection limit of 3×105 molecules/(cm3·min) for OH and 1×106 molecules/(cm5·min) for HO2. Its coupling to a photolysis cell enables the measurement of the total reactivity of the hydroxyl radical in ambient air and kinetic studies in laboratory. Two configurations have been considered: one with the photolysis cell at 90° to the FAGE nozzle, the other on line with the FAGE nozzle. The two configurations have been tested and validated by measuring the well known rate constants of OH with CH4, C3H8 and CO. The advantages and drawbacks of each configuration have been evaluated. The “on line” configuration limits losses and permits measurements over a larger reactivity range but is affected by OH formation from the laser beam striking the FAGE nozzle, thus limiting the ability to carry out energy dependence studies which can, in contrast, be successfully performed in the 90° configuration. 相似文献
118.
119.
目的保证叶片结构的完整性。方法采用结构工作变形分析理论,借助扫描式激光多普勒测振仪多点、非接触、高精度测量的优点,搭建了一套发动机叶片工作变形分析试验系统。通过振动台对叶片施加快速正弦扫频的基础激励,用测振仪测量叶片表面55个测点的速度响应,然后用工作变形分析方法得到该叶片的前6阶固有频率和振型,用模态置信准则评估上述6阶振型之间的相关性。结果该叶片振型由低阶到高阶依次是一阶弯曲、两种不同节线的一阶扭转、二阶弯曲、二阶扭转、弯扭耦合,不同阶次振型的MAC值都小于或等于0.2。结论不同模态振型之间的相关性很低,证明了工作变形分析结果的正确性。 相似文献
120.
C. di Marco U. Skiba K. Weston K. Hargreaves D. Fowler 《Water, Air, & Soil Pollution: Focus》2004,4(6):143-149
In order to assess nitrous oxide (N2O) emissions from typical intensively managed grassland in northern Britain fluxes were measured by eddy covariance using tuneable diode laser absorption spectroscopy from June 2002 to June 2003 for a total period of 4000 h. With micrometeorological techniques it is possible to obtain a very detailed picture of the fluxes of N2O at field scale (103–104 m2), which are valuable for extrapolation to regional scales. In this paper three of the four fertilizer applications were investigated in detail. N2O emissions did not always show a clear response. Hourly fluxes were very large immediately after the June 2002 nitrogen fertilizer application, peaking at 2.5 mg N2O–N m–2 s–1. Daily fluxes were averaging about 300 ng N2O m–2 s–1 over the 4 days following fertilizer application. The response of N2O emissions was less evident after the August fertilization, although 2 days after fertilizer application an hourly maximum flux of 554 ng N2O–N m–2 s–1 was registered. For the rest of August the flux was undetectable. The differences between fertilization events can be explained by different environmental conditions, such as soil temperature and rainfall. A fertiliser-induced N2O emission was not observed after fertilizer application in March 2003, due to lack of rainfall. The total N2O flux from June 2002 to June 2003 was 5.5 kg N2O–N ha–1y–1, which is 2.8% of the total annual N fertilizer input. 相似文献