全文获取类型
| 收费全文 | 40篇 |
| 免费 | 3篇 |
| 国内免费 | 10篇 |
专业分类
| 测绘学 | 1篇 |
| 大气科学 | 7篇 |
| 地球物理 | 15篇 |
| 地质学 | 17篇 |
| 海洋学 | 11篇 |
| 自然地理 | 2篇 |
出版年
| 2021年 | 1篇 |
| 2018年 | 2篇 |
| 2017年 | 2篇 |
| 2016年 | 1篇 |
| 2015年 | 4篇 |
| 2014年 | 4篇 |
| 2013年 | 3篇 |
| 2012年 | 4篇 |
| 2011年 | 3篇 |
| 2010年 | 2篇 |
| 2009年 | 2篇 |
| 2008年 | 1篇 |
| 2007年 | 4篇 |
| 2006年 | 2篇 |
| 2004年 | 3篇 |
| 2003年 | 1篇 |
| 2001年 | 1篇 |
| 2000年 | 2篇 |
| 1999年 | 2篇 |
| 1998年 | 2篇 |
| 1997年 | 4篇 |
| 1996年 | 1篇 |
| 1995年 | 1篇 |
| 1991年 | 1篇 |
排序方式： 共有53条查询结果，搜索用时 31 毫秒
31.
32.
33.
近年来,胶州湾和莱州湾海域污染日益严重,引起国家有关部门和省政府的高度重视,并采取了措施加以控制和减少污染,但治理效果并不显著。本文对两湾纳污区的污染源进行了分析,探讨了导致近年来治理效果不佳的原因,并提出综合治理对策。 相似文献
34.
An efficient and systematic procedure is proposed for finding the optimal damper positioning to minimize the dynamic compliance of a 3-D shear building model. The dynamic compliance is expressed in terms of the transfer function amplitudes of the local interstorey drifts evaluated at the undamped fundamental natural frequency. The dynamic compliance is minimized subject to a constraint on the sum of the damping coefficients of added dampers. Optimality criteria are derived and the optimal damper positioning is determined via an original steepest direction search algorithm. This algorithm enables one to find an optimal damper positioning sequentially for gradually increasing damper capacity levels. A non-monotonic design path with respect to the total damper capacity level often appears in the application of this algorithm. A new augmented algorithm via parameter switching is devised to find this non-monotonic design path. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
35.
The compliance enforcement system of the Kyoto Protocol provides only weak incentives for Parties to comply with their commitments. For example, the penalties for non-compliant countries are not legally binding, and moreover, there is no second-order punishment for those countries that fail to implement them. Thus, a Party can simply refuse to comply without consequence. The alternative compliance enforcement systems that have been proposed in the literature also face substantial problems. A simple, flexible, potent, and credible compliance enforcement system for a post-Kyoto climate agreement, based on deposits, is proposed here: at ratification, each country deposits a significant amount of money, and continues to do so in the preparation stage each year until the start of the commitment period. At the end of this period, those countries that meet their emissions limitation targets receive a full refund of their deposit, while those that fail to do so forfeit part or all of it. A simplified two-country model of the deposit system and a numerical example of an agreement involving the US, Japan, Russia, and Europe is also provided. If each country's deposit is no less than its abatement costs, there is a strong incentive for participating countries to avoid non-compliance. 相似文献
36.
《Marine Policy》2015
Through textual analysis, this paper takes into account documentary evidence of the Auditor-General׳s audit commentaries of the reporting compliance of the National Fisheries Authority of Papua New Guinea for the period 2006–2012. The results of the analysis show that the National Fisheries Authority׳s financial statements are late, unprepared or qualified. The study suggests ways the authority might improve its reporting compliance at relatively little cost, and how using national reporting compliance instruments may enhance national fisheries policy. The findings are of critical importance for fishing authority local managers, policy-makers and practitioners interested in providing compliant financial and operational reporting to meet the decision needs of its key stakeholders. 相似文献
37.
38.
In this paper, we consider the upscaling of Hooke's law and its parameters on the fine scale, to a similar law with upscaled parameters on a larger scale. It is assumed that the fine scale material properties of the rock are imperfectly layered. In the governing equations, the deviations from perfect layering introduce a small parameter that can be used in perturbation series expansions for the stress, the strain, and the displacement. In the approximation of order zero the upscaled compliance matrix contains the well-known Backus parameters; this approximation holds exactly for a perfect layering. However, many natural rock types are imperfectly layered and in that case the approximation of order zero may not be sufficiently accurate. Therefore, we consider also the first order corrections. The derivation and results are presented both for the most general case and for the much simpler case in which the fine scale Poisson ratio may be assumed constant. From thermodynamic principles, it follows that the compliance tensor is symmetric on the fine scale. However, it is shown that the argument for symmetry cannot be extended to upscaled rigidities. One of the most important conclusions is that upscaled compliance tensors are nonsymmetric when there are trends in the deviations from perfect layering. 相似文献
39.
恒载作用下轴对称圆巷围岩的流变变形方程求解 总被引：1，自引：0，他引：1
建立围岩-支护相互作用流变变形机制的数学力学模型是解决岩石地下工程支护问题的有效途径,其关键问题是,在围岩产生流变变形的过程中支护是如何对围岩进行作用的。根据基于Levy-Mises本构关系及D-P屈服准则的轴对称圆巷的理想弹塑性解、一维蠕变曲线的等时曲线相似的假设以及三维流变试验结果,推导出了原岩应力和被动支护反力均为恒载,且巷道围岩为三维应力状态下的蠕变方程及轴对称圆巷围岩的非线性黏弹塑性流变变形计算公式。与前人的工作相比,文中推导的公式中含有对围岩流变变形起决定作用的2个参数,即原岩应力 和岩石材料的单轴塑性屈服应力 ,因此公式推导的理论基础更加完备、可信度更高。 相似文献
40.
