全文获取类型
收费全文 | 164篇 |
免费 | 41篇 |
国内免费 | 50篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 153篇 |
地球物理 | 63篇 |
地质学 | 26篇 |
海洋学 | 7篇 |
天文学 | 1篇 |
综合类 | 1篇 |
自然地理 | 3篇 |
出版年
2024年 | 1篇 |
2022年 | 6篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 6篇 |
2012年 | 7篇 |
2011年 | 1篇 |
2010年 | 6篇 |
2009年 | 6篇 |
2008年 | 16篇 |
2007年 | 11篇 |
2006年 | 12篇 |
2005年 | 19篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 11篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 13篇 |
1978年 | 12篇 |
排序方式: 共有255条查询结果,搜索用时 0 毫秒
51.
承德市臭氧污染气象条件预报方法研究 总被引:1,自引:0,他引:1
利用2014-2016年承德市环境监测站和气象站的数据,分析了气象条件对承德市O3-8h浓度的影响,探讨了臭氧污染气象条件的预报方法。结果表明:4-7月是承德市O3-8h浓度较高的月份,O3浓度的日变化特征为午后浓度高而夜间浓度低;O3污染的天气形势为500 hPa受高压脊和偏西气流影响,850 hPa有强暖平流和20℃以上的高温,地面受低压前部和高压后部之间的偏南气流影响;有利于O3-8h出现高浓度的气象因子为日平均气温大于23℃、日最高气温大于28℃、日平均海平面气压995-1007 hPa、日平均水汽压18-28 hPa、偏南风大于1 m·s-1。利用气象因子综合评分建立臭氧污染指数,与O3-8h浓度的相关系数高达0.7553,说明臭氧污染指数能较好地预报臭氧污染天气。 相似文献
52.
臭氧在卤虫卵孵化中的应用效果研究 总被引:4,自引:0,他引:4
臭氧因具有强氧化性,可以起到灭菌、消毒、净化水质的作用 ,并且它在水中可迅速分解为氧气,不会造成对水体的污染[1,8,9],被认为是一种绿色环保型的“消毒剂” ,因而在水产养殖中的应用越来越广泛。以往人们的研究主要集中在臭氧对养殖鱼类的毒性及水体的杀菌效果等方面[5,6,8] 另有报道臭氧影响微藻中的脂肪酸和蛋白质的含量[7]。有关臭氧对卤虫卵孵化率的影响仅见有孙广明等[2]报道 :利用臭氧处理过的水进行卤虫卵孵化,可使其孵化率提高10%以上。但有关卤虫卵孵化的最佳臭氧浓度、臭氧对卤虫无节幼体的成活率影响、… 相似文献
53.
54.
D.G. Kaskaoutis H.D. Kambezidis Shailesh Kumar Kharol K.V.S. Badarinath 《Atmospheric Research》2007,86(3-4):286-296
This study focuses on the determination of optical depths caused by ozone and trace gases absorption in the Chappuis band, 500–700 nm, and the contribution to the Total Minus Rayleigh Optical Depth (TMROD). The optical depths were derived using the transmission functions implemented in the SMARTS parametric model, while the Total Optical Depths (TODs) were derived by solar extinction measurements obtained in Athens during May 1995. From the data analysis it is obvious that both the ozone and trace gases contribute significantly to TMROD in the Chappuis band. More specifically, the trace gases contributions are higher for air with high pollution levels, while ozone's contribution can be significant under clear-sky conditions. Therefore, the correction in TMROD due to ozone and trace gases optical depths is necessary for an accurate determination of the Aerosol Optical Depth (AOD) in the Chappuis band. The optical depth of ozone is generally removed during the process of the AOD retrievals, since the significance of its absorption in the Chappuis band is well understood. Nevertheless, the optical depth of the trace gases (mainly NO2) is not always taken into account in the AOD retrievals, though its contribution can be significant in urban polluted atmospheres. In this respect, the present study attempts to quantify the ozone and trace gases contributions in an urban environment and to provide some new functions that help estimate the contribution of ozone to the TMROD in the Chappuis band. 相似文献
55.
56.
R. Toumi 《Journal of Atmospheric Chemistry》1992,15(1):69-77
The possibility of significant autocatalytic ozone production in the middle atmosphere has been demonstrated by Toumi et al. A detailed framework including five processes previously not considered is presented here. When these processes are included, particularly wavelength-dependent vibrational distributions of O2, calculated ozone enhancements are less than 10% in the upper stratosphere and lower mesosphere. The vibrational distributions and the rate of vibrational quenching are identified as key issues which need to be addressed by experiments. 相似文献
57.
非均相化学过程在青藏高原臭氧低谷形成中的作用 总被引:1,自引:0,他引:1
分析SAGE II资料发现:青藏高原对流层顶最高不超过17.6 km,夏季平均在17 km以下:来自对流层中低层的物质很少能被输送到17.5 km以上,来自对流层中低层的输送不会长时间持续地影响17.5 km以上的区域。青藏高原以及同纬度地区在15 20 km高度温度低于210 K,非均相化学反应可能在此起着重要作用。夏季青藏高原臭氧低谷的形成高度主要是15—20km,而且是长时间持续性的。分析结果显示:15—20km非均相化学过程在夏季青藏高原臭氧低谷的形成中可能起重要作用,特别在17.5—20km高度其所起的作用可能是主要的;而在17.5 km以下,从以往的研究可以知道青藏高原的动力和热力作用对夏季青藏高原臭氧低谷的形成起着主要作用。在春季和秋季,青藏高原上15—20km的臭氧"亏损"也可能是由于非均相化学过程造成的,使得青藏高原臭氧低谷每年从4月持续到10月。并且,影响非均相化学过程的主导因素可能是温度。 相似文献
58.
Temporal Surface Ozone Patterns in Urban Manitoba, Canada 总被引:1,自引:0,他引:1
This study examined temporal surface ozone patternsfor two urban centres in Manitoba,Canada by analyzing hourly concentrations at theWinnipeg downtown (1995–1999), Winnipegresidential (1995–1999) and Brandon industrial(1998–1999) monitoring sites. The characteristicannual ozone cycle and diurnalcycles for June and December were attributable to: (1) theannual and diurnal solar radiation cycles,(2) temporal variations in the emissions of precursorchemical compounds, in particular the source strength ofnitrogen oxides, (3) temporal variationsin the height of the mixed layer, which determinethe degree of dilution of these emissions byatmospheric dispersion, and (4) an in situvolatile organic compound sensitive photochemicalregime, which resulted in decreased concentrations ofozone in response to increasedconcentrations of nitrogen oxides. Onlyone exceedance of the maximum acceptable level of82 ppb was recorded in the study period; itoccurred at the Brandon monitoring site on June 6, 1999.The sequence of weather and the hourly concentrationsof ozone and nitrogen oxides indicatedthat: (1) ozone fumigation, with the transition fromthe nocturnal boundary layer to the daytime mixed layer, mayhave supplemented photochemical ozone formation duringthe morning hours, and (2) during theevening hours, the post cold-frontal downward flux ofozone rich air, which was in the region dueto atmospheric transport, stratosphere-troposphere-exchangeor, possibly, due to the multiplicityof thunderstorms in the area in lateafternoon – early evening, may have been the main cause ofthis rare exceedance event. 相似文献
59.
60.
Temporal variations in surface ozone and its precursors and meteorological effects at an urban site in China 总被引:3,自引:2,他引:3
Continuous measurements of ozone and its precursors including NO, NO2, and CO at an urban site (32°03′N, 118°44′E) in Nanjing, China during the period from January 2000 to February 2003 are presented. The effects of local meteorological conditions and distant transports associated with seasonal changed Asian monsoons on the temporal variations of O3 and its precursors are studied by statistical, backward trajectory, and episode analyses. The diurnal variation in O3 shows high concentrations during daytime and low concentrations during late night and early morning, while the precursors show high concentrations during night and early morning and low concentrations during daytime. The diurnal variations in air pollutants are closely related to those in local meteorological conditions. Both temperature and wind speed have significant positive correlations with O3 and significant negative correlations with the precursors. Relative humidity has a significant negative correlation with O3 and significant positive correlations with the precursors. The seasonal variation in O3 shows low concentrations in late autumn and winter and high concentrations in late spring and early summer, while the precursors show high concentrations in late autumn and winter and low concentrations in summer. Local mobile and stationary sources make a great contribution to the precursors, but distant transports also play a very important role in the seasonal variations of the air pollutants. The distant transport associated with the southeastern maritime monsoon contributes substantially to the O3 because the originally clean maritime air mass is polluted when passing over the highly industrialized and urbanized areas in the Yangtze River Delta. The high frequency of this type of air mass in summer causes the fact that a common seasonal characteristic of surface O3 in East Asia, summer minimum, is not observed at this site. The distant transports associated with the northern continental monsoons that dominate in autumn and winter are related to the high concentrations of the precursors in these two seasons. This study can contribute to a better understanding of the O3 pollution in vast inland of China affected by meteorological conditions and the rapid urbanization and industrialization. 相似文献