全文获取类型
| 收费全文 | 18303篇 |
| 免费 | 2333篇 |
| 国内免费 | 2890篇 |
专业分类
| 测绘学 | 4536篇 |
| 大气科学 | 3128篇 |
| 地球物理 | 2167篇 |
| 地质学 | 4483篇 |
| 海洋学 | 1787篇 |
| 天文学 | 470篇 |
| 综合类 | 1555篇 |
| 自然地理 | 5400篇 |
出版年
| 2024年 | 71篇 |
| 2023年 | 219篇 |
| 2022年 | 833篇 |
| 2021年 | 980篇 |
| 2020年 | 895篇 |
| 2019年 | 901篇 |
| 2018年 | 765篇 |
| 2017年 | 1032篇 |
| 2016年 | 1040篇 |
| 2015年 | 1032篇 |
| 2014年 | 1091篇 |
| 2013年 | 1455篇 |
| 2012年 | 1259篇 |
| 2011年 | 1158篇 |
| 2010年 | 885篇 |
| 2009年 | 982篇 |
| 2008年 | 1001篇 |
| 2007年 | 1110篇 |
| 2006年 | 1044篇 |
| 2005年 | 924篇 |
| 2004年 | 852篇 |
| 2003年 | 712篇 |
| 2002年 | 553篇 |
| 2001年 | 473篇 |
| 2000年 | 413篇 |
| 1999年 | 313篇 |
| 1998年 | 291篇 |
| 1997年 | 250篇 |
| 1996年 | 206篇 |
| 1995年 | 140篇 |
| 1994年 | 145篇 |
| 1993年 | 112篇 |
| 1992年 | 99篇 |
| 1991年 | 50篇 |
| 1990年 | 48篇 |
| 1989年 | 37篇 |
| 1988年 | 36篇 |
| 1987年 | 25篇 |
| 1986年 | 19篇 |
| 1985年 | 25篇 |
| 1984年 | 16篇 |
| 1983年 | 8篇 |
| 1982年 | 5篇 |
| 1981年 | 5篇 |
| 1980年 | 7篇 |
| 1978年 | 1篇 |
| 1976年 | 1篇 |
| 1971年 | 2篇 |
| 1954年 | 5篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
91.
J. Perbos P. Escudier F. Parisot G. Zaouche P. Vincent Y. Menard F. Manon G. Kunstmann D. Royer L. -L. Fu 《Marine Geodesy》2003,26(3):147-157
On 7 December 2001, Jason-1 was successfully launched by a Boeing Delta II rocket from the Vandenberg Air Force Base, California. The Jason-1 satellite will maintain the high accuracy altimeter service provided since 1992 by TOPEX/Poseidon (T/P), ensuring the continuity in observing and monitoring the Ocean Dynamics (intraseasonal to interannual changes, mean sea level, tides, etc.). Despite one-fourth the mass and power, the Jason-1 system has been designed to have basically the same performance as T/P, measuring sea surface topography at a centimetric level. This new CNES/NASA mission also provides near real-time data for sea state and ocean forecast. The first two months of the Jason-1 mission have been dedicated to the assessment of the overall system. The goals of this assessment phase were:
1. To assess the behavior of the spacecraft at the platform and payload levels (Jason-1 being the first program to call on the PROTEUS versatile multimission platform for Low and Medium Earth Orbit Missions developed in partnership between Alcatel Space and CNES);
2. To verify that platform performance requirements are met with respect to Jason-1 requirements;
3. To verify that payload instruments performance requirements evaluated at instrument level are met;
4. To assess the performance of the Jason-1 Ground System.
This article will display the main outputs of the assessment of the system. It will demonstrate that all the elements of the onboard and ground systems are within the specifications. Provision of data to the Jason-1 Science Working Team started at the end of March 2002. This is the goal of a six-month phase after closure of the initial assessment phase to derive the error budget of the system in terms of altimetry user products. 相似文献
1. To assess the behavior of the spacecraft at the platform and payload levels (Jason-1 being the first program to call on the PROTEUS versatile multimission platform for Low and Medium Earth Orbit Missions developed in partnership between Alcatel Space and CNES);
2. To verify that platform performance requirements are met with respect to Jason-1 requirements;
3. To verify that payload instruments performance requirements evaluated at instrument level are met;
4. To assess the performance of the Jason-1 Ground System.
This article will display the main outputs of the assessment of the system. It will demonstrate that all the elements of the onboard and ground systems are within the specifications. Provision of data to the Jason-1 Science Working Team started at the end of March 2002. This is the goal of a six-month phase after closure of the initial assessment phase to derive the error budget of the system in terms of altimetry user products. 相似文献
92.
93.
94.
研究流形上的聚类分析，针对基于密度的空间聚类引入了流形概念，提出1种基于流形的密度聚类算法，该方法将流形的概念与聚类相结合，可以适用于样本为复杂分布的聚类。文中通过实例证明此算法的有效性。 相似文献
95.
96.
Presented here is a compact explicit difference scheme of high accuracy for solving the extended Boussinesq equations.For time discretization,a three-stage explicit Runge-Kutta method with TVD property is used at predicting stage,a cubic spline function is adopted at correcting stage,which made the time discretization accuracy up to fourth order;For spatial discretization,a three-point explicit compact difference scheme with arbitrary order accuracy is employed.The extended Boussinesq equations derived by Beji and Nadaoka are solved by the proposed scheme.The numerical results agree well with the experimental data.At the same time,the comparisons of the two numerical results between the present scheme and low accuracy difference method are made,which further show the necessity of using high accuracy scheme to solve the extended Boussinesq equations.As a valid sample,the wave propagation on the rectangular step is formulated by the present scheme,the modelled results are in better agreement with the experimental data than those of Kittitanasuan. 相似文献
97.
98.
99.
100.
应用多年的实测资料 ,分析了曹娥江河口高水位成因 ,结果表明 ,曹娥江河口洪水位具有山溪性和可冲性的特点 ,人类活动对高水位有较大影响。应用统计分析法和成因分析法推求 1 %设计高水位 ,讨论了成因分析法中上、下边界条件的选取 ,其选取原则对其他潮汐河口确定设计高水位具有借鉴意义 相似文献