全文获取类型
收费全文 | 84篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 8篇 |
地球物理 | 21篇 |
地质学 | 24篇 |
海洋学 | 20篇 |
天文学 | 12篇 |
综合类 | 1篇 |
自然地理 | 3篇 |
出版年
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 4篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 8篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 2篇 |
1996年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有90条查询结果,搜索用时 15 毫秒
1.
2.
Validation of the stochastic distorted-wave Born approximation model with broad bandwidth total target strength measurements of Antarctic krill 总被引:2,自引:0,他引:2
In the computations of SDWBATTS(f) in Figure 4, the scatteredvector was integrated over all orientations in the XY plane,where X is the main axis of the krill, but a factor of 2 was 相似文献
3.
4.
5.
This document explores the possibilities of multiscale expansions and domain decomposition to solve part of the Couplex 1 exercise. We concentrate on the hydrostatic pressure and show that the slenderness of the domain and the large variations of the Darcy constants allows an analytical approximation which our test reveals to be true to relative errors smaller than 10–3. The numerical tests are done in 2D with freefem+ and in 3D with freefem3D. Some considerations are also given for Iodine transport. 相似文献
6.
The highly aromatic structure of the macromolecular organic matter (OM) of the Murchison and Orgueil meteorites was recently shown to contain free organic radicals which are concentrated in micro-regions in contrast with terrestrial samples which always show an homogeneous distribution of radicals. An additional signature is revealed, in the present study, by the evolution of the radical concentration with temperature. Whereas in terrestrial samples, this concentration is independent of temperature (Curie magnetism), a significant increase is observed above 150 K in the two meteorites. Based on the electronic structure of organic radicals, calculated by Extended Hückel and Density Functional methods, this behavior was assigned to the occurrence of diradicaloid moieties hosted by aromatic structures of 10 to 15 rings and having a quinoidal structure. They represent 40 and 25% of the total radicals in Orgueil and Murchison, respectively. The search for the cosmochemical interpretation of this unique observation should open a new field of experimental investigations. 相似文献
7.
8.
Thomas Binet Pierre Failler Pablo N. Chavance Mohamed Abidine Mayif 《Global Environmental Change》2013,23(6):1434-1443
This article investigates whether the European Union-Mauritania fisheries agreement, which allocates part of the Europe's financial contribution to the conservation of marine ecosystems located within the Banc d’Arguin National Park, can be regarded as a payment for ecosystem service. A framework for qualification as such payment scheme was established based on an extensive literature review. The criteria identified for the qualification as a payment to ecosystem service pertain to: (1) the definition of the ecosystem service(s) involved; (2) the mechanism involved by the payment; and (3) the nature of the transaction. Interviews with local beneficiaries and subsequent data analysis led to the conclusion that this mechanism could be regarded as a payment to ecosystem service and so, through the European Union-Mauritania Fisheries agreement, the European Union were investing to protect local fish resources that could be exploited by its fishing fleet. This agreement, involving the first International Payment to Ecosystem Service of this kind, marks an important step towards better consideration of marine conservation in international public policy and foreign fishing policy in particular. However, this payment is small when compared to revenues generated through the exploitation of developing countries’ fishing grounds by fishing countries. Nevertheless it opens the door for more detailed applications of payment to ecosystem service schemes to other ecosystems contexts, and can provide a useful alternative source of financing of marine biodiversity conservation. 相似文献
9.
In the caption for Figure 5, it was erroneously stated thatthe TS curves were normalized to L = 31.6 mm. They were normalizedto L = 38.35 相似文献
10.
Ali Salim Joodi Stanislas Sizaret Stéphane Binet Ary Bruand Patrick Alberic Michel Lepiller 《Hydrogeology Journal》2010,18(2):295-309
Darcy’s law is the equation of reference widely used to model aquifer flows. However, its use to model karstic aquifers functioning with large pores is problematic. The physics occurring within the karstic conduits requires the use of a more representative macroscopic equation. A hydrodynamic model is presented which is adapted to the karstic aquifer of the Val d’Orléans (France) using two flow equations: (1) Darcy’s law, used to describe water flow within the massive limestone, and (2) the Brinkman equation, used to model water flow within the conduits. The flow equations coupled with the transport equation allow the prediction of the karst transfer properties. The model was tested by using six dye tracer tests and compared to a model that uses Darcy’s law to describe the flow in karstic conduits. The simulations show that the conduit permeability ranges from 5?×?10?6 to 5.5?×?10?5?m2 and the limestone permeability ranges from 8?×?10?11 to 6?×?10?10?m2. The dispersivity coefficient ranges from 23 to 53 m in the conduits and from 1 to 5 m in the limestone. The results of the simulations carried out using Darcy’s law in the conduits show that the dispersion towards the fractures is underestimated. 相似文献