全文获取类型
收费全文 | 52篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
综合类 | 10篇 |
化学工业 | 5篇 |
金属工艺 | 1篇 |
建筑科学 | 11篇 |
矿业工程 | 8篇 |
能源动力 | 6篇 |
轻工业 | 4篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
冶金工业 | 2篇 |
自动化技术 | 8篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2016年 | 1篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有57条查询结果,搜索用时 15 毫秒
1.
大别山地区是一地球物理场变异带,大别隆起的北界是桐柏—晓天断裂系,南界是桐柏—浠水断裂系,东界是郯庐断裂系,三个壳型断裂所围截的“V”形三角地块呈—北厚南薄的楔形变质地块,楔于东秦岭褶皱带中。区内主要金银多金属矿产,受桐柏—晓天断裂系和桐柏—浠水断裂系的控制,桐柏—大悟—圻春为—含金聚矿构造带。 相似文献
2.
利用一个森林小流域的水文、气象资料,通过确定性水文模拟方法,探索了该地区的水文特性。通过分析,发现该流域水资源十分丰富,河川径流变化平缓,有利于综合开发利用。并提出了林冠能截留大量降水,森林土壤能贮蓄大量水分、调节径流成分并能消减洪峰,坦化出流过程的结论。 相似文献
3.
山西王莽岭风景区国内客源市场分析及定位研究 总被引:1,自引:0,他引:1
赵霞 《河南机电高等专科学校学报》2011,19(4):36-38,52
在问卷调查的基础上,对王莽岭的国内客源市场从人口、行为、心理及地域结构进行了细分,找出了对景区具有显著影响的五个核心变量,即年龄、收入、旅游方式、旅游动机及地域结构,然后根据以上五个核心细分变量对景区的国内客源市场进行了定位。 相似文献
4.
数据基础设施是智慧景区的重要组成部分,云计算将是实现智慧黄山景区的重要支撑技术.在分析黄山景区规划管理信息化需求、总结黄山景区现有信息化成果、论述当前云计算技术发展的基础上,提出了基于云计算构建智慧黄山景区数据基础设施——云数据中心的规划方案,包括构建云数据中心的原则与内容;探讨了智慧黄山景区云数据中心的实施策略,包括构建私有云数据中心、拓展混合云数据中心以及4个阶段的建设生命周期.对我国智慧景区数据基础设施建设进行了有益的探索. 相似文献
5.
Lee K Hur SD Hou S Hong S Qin X Ren J Liu Y Rosman KJ Barbante C Boutron CF 《The Science of the total environment》2008,404(1):171-181
A series of 42 snow samples covering over a one-year period from the fall of 2004 to the summer of 2005 were collected from a 2.1-m snow pit at a high-altitude site on the northeastern slope of Mt. Everest. These samples were analyzed for Al, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Cd, Sb, Pb, and Bi in order to characterize the relative contributions from anthropogenic and natural sources to the fallout of these elements in central Himalayas. Our data were also considered in the context of monsoon versus non-monsoon seasons. The mean concentrations of the majority of the elements were determined to be at the pg g(-1) level with a strong variation in concentration with snow depth. While the mean concentrations of most of the elements were significantly higher during the non-monsoon season than during the monsoon season, considerable variability in the trace element inputs to the snow was observed during both periods. Cu, Zn, As, Cd, Sb, and Bi displayed high crustal enrichment factors (EF(c)) in most samples, while Cr, Ni, Rb, and Pb show high EF(c) values in some of the samples. Our data indicate that anthropogenic inputs are potentially important for these elements in the remote high-altitude atmosphere in the central Himalayas. The relationship between the EF(c) of each element and the Al concentration indicates that a dominant input of anthropogenic trace elements occurs during both the monsoon and non-monsoon seasons, when crustal contribution is relatively minor. Finally, a comparison of the trace element fallout fluxes calculated in our samples with those recently obtained at Mont Blanc, Greenland, and Antarctica provides direct evidence for a geographical gradient of the atmospheric pollution with trace elements on a global scale. 相似文献
6.
"龙安寺方丈庭园"是日本具有代表性的庭园,但其建造时期、建造者、建造意图都未有定论。本文认为此园是对中国五台山的描绘。自古以来五台山的文殊菩萨信仰非常兴盛,从8世纪开始有多位来自日本的高僧到访过五台山,并将佛像、绘画等带回了日本。以此为依据在13世纪绘制而成的"五台山文殊菩萨骑狮像",中央石峰的形态与"龙安寺方丈庭园"中央置石组群造型相同,可以推断"五台山文殊菩萨骑狮像"中的石峰是其描摹的原型。 相似文献
7.
8.
从宁夏广武山铜矿矿化特征分析成矿原因,试图找出成矿规律.在已有资料的基础上,研究了该地区含矿地层区域铜矿化特征.结果表明,该地区原生黄铜矿型铜矿的原生沉积和次生富集的发生与褪色带关系密切,形成似层状矿体.退色带中铜矿化是氧化-还原过渡带环境的产物,是成矿的有利部位.广武山地区寻找铜矿应注意研究相对应的有利地质成矿部位,可望有新的发现和突破. 相似文献
9.
Udo Blum 《Journal of chemical ecology》1997,23(2):347-362
The effectiveness of various citrate extractions to recover ferulic acid, a phenolic acid, from Cecil Ap and Bt soil and plant surface debris (crimson clover, rye, subterranean clover, and wheat) was compared with that of EDTA extractions. Citrate extractions were equivalent to or better than EDTA in recovering phenolic acids from soil and plant debris. Citrate, unlike EDTA, did not interfere with the Folin & Ciocalteu's phenol reagent when determining total phenolic acid content in soil and plant debris extracts. Care, however, must be taken when using Folin & Ciocalteu's phenol reagent to estimate total phenolic acid content, particularly in the presence of soil organic matter. Citrate was also more effective in extracting phenolic acids from A-horizon soils. Thus, citrate extractions overcome some of the major limitations observed for EDTA extractions. 相似文献
10.
Jennifer E Kay Alan R GillespieGary B Hansen Erin C Pettit 《Remote sensing of environment》2003,86(2):216-231
We use multispectral MODIS/ASTER Airborne Simulator (MASTER) data collected at Mt. Rainier, Washington (USA) to map spatial covariance between snowpack properties and to evaluate techniques for quantitative estimation of reflectance, grain size, and temperature. The late-August MASTER images reveal a distinct pattern of snow contaminant content, grain size, and temperature related to a recent snowfall and late-summer melting. Spatial correlation between grain size and temperature patterns suggests that rapid destructive metamorphism of the fresh snow occurred when temperatures were near 0 °C. We use 10 specific locations to evaluate hemispherical-directional reflectance factor (HDRF), grain size, and temperature retrievals. We map relative snow contaminant content using visible (0.4-0.8 μm) HDRF spectra. Atmospheric correction and topographic modeling limit the accuracy of HDRF estimates. We use MASTER-derived spectra near 1.8 and 2.2 μm to estimate optical grain size (by comparison to modeled layers of ice spheres) and physical grain size (by comparison to measured spectra with known physical grain size and by correlation to ground measurements). Estimated physical grain sizes were less than estimated optical grain sizes. Differing definitions of optical and physical grain sizes could contribute to this discrepancy. Limitations at 1.8 and 2.2 μm, including reduced discrimination between larger grain radii (>∼500 μm physical, >∼200 μm optical) and low signal-to-noise ration with atmospheric effects and decreasing solar irradiance, suggest that grain size retrieval may be improved at other wavelengths (e.g., 1.1 μm). Accounting for uncertainty in emissivity, atmospheric correction, and detector noise, we estimate systematic errors in our radiant temperatures at <1.8 °C. This study shows both strengths and limitations for coregistered visible, short-wave infrared, and thermal infrared images to estimate snowpack properties and reveal their spatial coherence. 相似文献