全文获取类型
收费全文 | 67篇 |
免费 | 4篇 |
国内免费 | 11篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 3篇 |
地球物理 | 11篇 |
地质学 | 32篇 |
海洋学 | 17篇 |
天文学 | 14篇 |
综合类 | 3篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2012年 | 4篇 |
2011年 | 1篇 |
2010年 | 3篇 |
2009年 | 7篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 2篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有82条查询结果,搜索用时 31 毫秒
61.
野外实验场地球物理电磁数据采集与分析 总被引:3,自引:0,他引:3
地球物理电磁数据观测实验场的建立在国内仍属空白,根据开展电磁法的方法技术要求,我们率先选择具备条件的已知矿区作为实验场地,开展了包括国内、外多种型号电磁法仪器(GDP 32Ⅱ、V8、DEM-V、DJS-8A)的相同装置下的同剖面同点位对比试验.对野外实验场上所开展的不同方法每种仪器的数据采集方式与取得结果进行比较分析,并与地质资料进行了结合分析;通过地球物理电磁数据的综合观测研究,形成标准化的数据,将对电磁法仪器开发、仪器引进提供实验检测场地与标准的检测数据,促进地球物理电磁探测技术的研究与发展. 相似文献
62.
The impact of a non-rigid seafloor on the wave climate at Cassino Beach, Brazil, May–June 2005 is studied using field measurements and a numerical wave model. The measurements consist of wave data at four locations; rheology and mud thickness from grab samples; and an estimate of the horizontal distribution of mud based on echo-soundings. The dissipation of waves by a non-rigid bottom is represented in the wave model by treating the mud layer as a viscous fluid. Applied for 431 time periods, the model without this type of dissipation has a strong tendency to overpredict nearshore wave energy, except during a period of large storm waves. Two model variations which include this dissipation have a modest tendency to underpredict the nearshore wave energy. An inversion methodology is developed and applied to infer an alternate mud distribution which, when used with the wave model, yields the observed waveheights. 相似文献
63.
Kristen M. Reifel Scott C. Johnson Paul M. DiGiacomo Michael J. Mengel Nikolay P. Nezlin Jonathan A. Warrick Burton H. Jones 《Continental Shelf Research》2009,29(15):1821-1835
The effects from two winter rain storms on the coastal ocean of the Southern California Bight were examined as part of the Bight ‘03 program during February 2004 and February–March 2005. The impacts of stormwater from fecal indicator bacteria, water column toxicity, and nutrients were evaluated for five major river discharges: the Santa Clara River, Ballona Creek, the San Pedro Shelf (including the Los Angeles, San Gabriel, and Santa Ana Rivers), the San Diego River, and the Tijuana River. Exceedances of bacterial standards were observed in most of the systems. However, the areas of impact were generally spatially limited, and contaminant concentrations decreased below California Ocean Plan standards typically within 2–3 days. The largest bacterial concentrations occurred in the Tijuana River system where exceedances of fecal indicator bacteria were noted well away from the river mouth. Maximum nitrate concentrations (~40 μM) occurred in the San Pedro Shelf region near the mouth of the Los Angeles River. Based on the results of general linear models, individual sources of stormwater differ in both nutrient concentrations and the concentration and composition of fecal indicator bacteria. While nutrients appeared to decrease in plume waters due to simple mixing and dilution, the concentration of fecal indicator bacteria in plumes depends on more than loading and dilution rates. The relationships between contaminants (nutrients and fecal indicator bacteria) and plume indicators (salinity and total suspended solids) were not strong indicating the presence of other potentially important sources and/or sinks of both nutrients and fecal indicator bacteria. California Ocean Plan standards were often exceeded in waters containing greater than 10% stormwater (<28–30 salinity range). The median concentration dropped below the standard in the 32–33 salinity range (1–4% stormwater) for total coliforms and Enterococcus spp. and in the 28–30 salinity range (10–16% stormwater) for fecal coliforms. Nutrients showed a similar pattern with the highest median concentrations in water with greater than 10% stormwater. Relationships between colored dissolved organic matter (CDOM) and salinity and between total suspended solids and beam attenuation indicate that readily measurable, optically active variables can be used as proxies to provide at least a qualitative, if not quantitative, evaluation of the distribution of the dissolved, as well as the particulate, components of stormwater plumes. In this context, both CDOM absorption and the beam attenuation coefficient can be derived from satellite ocean color measurements of inherent optical properties suggesting that remote sensing of ocean color should be useful in mapping the spatial areas and durations of impacts from these contaminants. 相似文献
64.
河北山前平原地下水^32Si年龄初探 总被引:6,自引:3,他引:3
^32Si是放射性同位素,半衰期约140a可以测定50~1000a地下水的年龄,本文用Fe(OH)3共沉淀法从天然水中提取SiO2回收率可达30%~98%,然后提取和纯化^32P,将H3PO4溶液和Pico-flour^TMLLT混合制备计数溶液,用液体闪烁计数法测量中^32P的放射性,本底计数为4.80cph,仪器效率为45.34%,然后用公式计算样品的^32Si放射性浓度和地下水的^32Si年 相似文献
65.
66.
67.
世界地质遗迹保护和地质公园建设的现状和展望 总被引:35,自引:1,他引:34
在2004年6月在中国北京召开了第一届世界地质公园大会和2004年8月在意大利佛罗伦萨举行第32届国际地质大会,来自五大洲数十个国家的地质学家和地质公园管理者发言,展示了各国地质遗产保护现状,地质公园建设中地质遗产的科学研究,公众教育;保护方法技术;与文化遗产的关系;与城市和区域发展规划的关系;与旅游产业发展的关系,地质公园与国家公园的关系;欧、美及非洲、大洋洲和亚洲各国地质公园发展前景等。他山之石,可以攻玉。对照各国的近况,我国在地质遗产的研究和保护方面要保持世界领先地位,在相关法规建设,地学背景研究,人才培养等方面还有大量工作要做。 相似文献
68.
C. del Burgo R. F. Peletier A. Vazdekis S. Arribas E. Mediavilla 《Monthly notices of the Royal Astronomical Society》2001,321(2):227-238
We present integral field spectroscopy of the circumnuclear region of M32 obtained with the 2D_FIS fibre optics spectrographs installed at the 4.2-m William Herschel Telescope. From these spectra line-strength maps have been made for about 20 absorption lines, mostly belonging to the Lick system. We find good agreement with long-slit line-strength profiles in the literature, and no radial gradients in the azimuthally averaged absorption line indices. We fit the mean values of each spectral index and colours from the literature for the inner regions of M32 to the models of Vazdekis et al. and Worthey, finding that the present data can be well interpreted for a single stellar population of an intermediate age (∼4 Gyr) and a metallicity similar to solar 相似文献
69.
利用Win32 API通信函数实现串口通信编程 总被引:1,自引:0,他引:1
测绘仪器与计算机之间的异步串行通信是现代测绘中经常遇到的问题,如何在Windows平台下实现测绘仪器与计算机之间数据通信是测量内、外业一体化的基本问题。在工作经验的基础上,详细研究和分析了利用Win32API通信函数实现串口通信编程的基本方法以及多线程技术在串口通信中的应用和特点,最后以大地型ASHTECHGPS接收机为研究对象,进行了相应的实验研究。 相似文献
70.
目前业内普遍使用的机械式海流计功耗大,连续工作时间短,姿态测量精度较低,体积较大,存储容量较小,维护复杂,在需要长时间进行海洋观测使用时十分不便。针对这一实际问题,为提高海流计的性能,设计以STM32f103ZE处理器为核心,运用现代锂离子电池技术,存储技术,传感器技术,无线充电技术,无线通信技术,对机械式海流计电子电路进行了重新设计。样机测试结果表明:该设计功耗低,流向精度高,维护简单且可长时间在水下稳定工作,完全满足各种海洋作业中海流测量需求,具有很大的实用价值。 相似文献