全文获取类型
收费全文 | 140篇 |
免费 | 15篇 |
国内免费 | 8篇 |
专业分类
测绘学 | 8篇 |
大气科学 | 15篇 |
地球物理 | 43篇 |
地质学 | 58篇 |
海洋学 | 7篇 |
天文学 | 20篇 |
综合类 | 6篇 |
自然地理 | 6篇 |
出版年
2024年 | 1篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 14篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 5篇 |
2012年 | 10篇 |
2011年 | 10篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 3篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有163条查询结果,搜索用时 31 毫秒
11.
介绍了2013~2014中国大陆构造环境监测网络的基本情况及西部地区绝对重力观测的情况,并对观测结果进行分析。结果表明,成果稳定性良好,89.5%的成果观测精度优于±5.00μGal,能够满足"陆态网络"的技术要求。 相似文献
12.
13.
Christopher Packham Keith L. Thompson Almudena Zurita Johan H. Knapen Ian Smail Robert Greimel Daniel F. M. Folha Chris Benn rew Humphrey Rene Rutten David Ciardi Matthieu Bec Richard Bingham Simon Craig Kevin Dee Derek Ives Paul Jolley Peter Moore Marti Pi i Puig Simon Rees Gordon Talbot Sue Worswick 《Monthly notices of the Royal Astronomical Society》2003,345(2):395-405
14.
The Hii regions S254, 255 and 257 in the constellation of Orion are close together on the sky and appear like a triple object. Fabry-Pérot radial velocities of the Hii regions as well asUBV photo-electric magnitudes of their exciting stars are obtained. The data show that (1) all three nebulae are at a distance of 2.5 kpc; (2) an excess extinction is observed in S255 and S257 while S254 shows no excess extinction; (3) S255, identified as an IR and a molecular source, is the youngest object of the group. It is concluded that the three Hii regions are at different evolutionary stages. 相似文献
15.
Performance of ENSEMBLES regional climate models over Central Europe using various metrics 总被引:1,自引:1,他引:0
Eva Holtanová Ji?í Mik?ovsky Jaroslava Kalvová Petr Pi?oft Martin Motl 《Theoretical and Applied Climatology》2012,108(3-4):463-470
We show the evaluation of ENSEMBLES regional climate models (RCMs) driven by reanalysis ERA40 over a region centered at the Czech Republic. Attention is paid especially to the model ALADIN-CLIMATE/CZ, being used as the basis of the new climate change scenarios simulation for the Czech Republic. The validation criteria used here are based on monthly or seasonal mean air temperature and precipitation. We concentrate not only on spatiotemporal mean values but also on temporal standard deviation, inter-annual variability, the mean annual cycle, and the skill of the models to represent the observed spatial patterns of these quantities. Model ALADIN-CLIMATE/CZ performs quite well in comparison to the other RCMs; we find its performance satisfactory for further use for impact studies. However, it is also shown that the results of evaluation of the RCMs’ skill in simulating observed climate strongly depend on the criteria incorporated for the evaluation. 相似文献
16.
17.
Simone Bizzi Marco Tangi Rafael J. P. Schmitt John Pitlick Hervé Piégay Andrea Francesco Castelletti 《地球表面变化过程与地形》2021,46(14):2946-2962
In this article we apply the CASCADE network-scale sediment connectivity model to the Vjosa River in Albania. The Vjosa is one of the last unimpaired braided rivers in Europe and, at the same time, a data scarce environment, which limits our ability to model how this pristine river might respond to future human disturbance. To initialize the model, we use remotely sensed data and modeled hydrology from a regional model. We perform a reach-by-reach optimization of surface grain size distribution (GSD) and bedload transport capacity to ensure equilibrium conditions throughout the network. In order to account for the various sources of uncertainty in the calculation of transport capacity, we performed a global sensitivity analysis. The modeled GSD distributions generated by the sensitivity analysis generally match the six GSDs measured at different locations within the network. The modeled bedload sediment fluxes increase systematically downstream, and annual fluxes at the outlet of the Vjosa are well within an order of magnitude of fluxes derived from previous estimates of the annual suspended sediment load. We then use the modeled sediment fluxes as input to a set of theoretically derived functions that successfully discriminate between multi-thread and single-thread channel patterns. This finding provides additional validation of the model results by showing a clear connection between modeled sediment concentrations and observed river morphology. Finally, we observe that a reduction in sediment flux of about 50% (e.g., due to dams) would likely cause existing braided reaches to shift toward single thread morphology. The proposed method is widely applicable and opens a new avenue for application of network-scale sediment models that aid in the exploration of river stability to changes in water and sediment fluxes. 相似文献
18.
绝对重力仪激光器光纤由于应力变化、形状改变、震动或耦合器维护等原因破坏了输出激光的偏振态,使其在光纤内的传输变得非常不稳定,导致光纤输出激光的消光比值小于100,无法满足绝对重力观测条件。针对该问题,介绍了光纤对准调节的方法,通过设计消光比检测装置检验消光比值是否大于100。对#181和#250两台WEO100型He-Ne激光器的光纤进行对准调节实验,并通过消光比检测装置实测,两台激光器输出的光束消光比值满足绝对重力测量的条件,表明该对准调节方法科学有效。 相似文献
19.
Low‐frequency passive integrated transponders (PIT tags), are commonly used for monitoring pebble mobility in gravel‐bed rivers. Although early studies reported high recovery rates for PIT tags used in small streams, recovery rates in larger systems remain low, substantially limiting the possibilities for their use in such rivers. These low recovery rates are potentially due to missed detections caused by tag signal collision, burial in the sediment layer deeper than the maximum detection range and insufficient (but still exhausting) field effort to cover the concerned areas. A potential solution for addressing these problems is to use active ultra‐high frequency (a‐UHF) transponders as these have a greater detection range and anti‐collision protocols. In order to assess the potential of such transponders for pebble tracking in rivers, we used 433.92 MHz COIN‐ID and COIN‐HC models (ELA Innovation Company, Montpellier, France). We completed several tests to (i) characterize transponder detection ranges in the water and in saturated sediment and (ii) develop field protocols for locating tags by combining global positioning systems (GPS) sites and transponder received signal strength indication (RSSI) levels. The results showed that (i) the maximum detection ranges are about 2.4 m in the water column and more than 2.6 m in a column of saturated gravelly‐sandy sediment, (ii) RSSI spatial interpolation can be used to determine transponder position with good accuracy (< 1 m), (iii) the desired minimal level of accuracy can be adjusted depending on in‐field effort and signal impulse interval, (iv) the RSSI maximal value observed cannot yet be used to determine transponder burial depth because of the multipath propagation of radio frequencies and the semi‐directional emission of the tag signal. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
20.
Multidimensional Toxicity of Rhamnolipid Extracts Obtained From Creosote‐Contaminated Soil 下载免费PDF全文