全文获取类型
收费全文 | 813篇 |
免费 | 78篇 |
国内免费 | 91篇 |
专业分类
测绘学 | 60篇 |
大气科学 | 15篇 |
地球物理 | 136篇 |
地质学 | 312篇 |
海洋学 | 320篇 |
天文学 | 4篇 |
综合类 | 122篇 |
自然地理 | 13篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2015年 | 9篇 |
2014年 | 1篇 |
2013年 | 8篇 |
2012年 | 2篇 |
2011年 | 89篇 |
2010年 | 52篇 |
2009年 | 112篇 |
2008年 | 27篇 |
2007年 | 22篇 |
2006年 | 39篇 |
2005年 | 41篇 |
2004年 | 129篇 |
2003年 | 73篇 |
2002年 | 65篇 |
2001年 | 25篇 |
2000年 | 16篇 |
1999年 | 39篇 |
1998年 | 47篇 |
1997年 | 38篇 |
1996年 | 16篇 |
1995年 | 33篇 |
1994年 | 19篇 |
1993年 | 22篇 |
1992年 | 17篇 |
1991年 | 12篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1966年 | 2篇 |
1960年 | 1篇 |
排序方式: 共有982条查询结果,搜索用时 15 毫秒
221.
Two- and three-dimensional finite element analysis programs for pile-soil interaction are compiled. Duncan-Chang's Model is used. The construction sequence of the pier is modeled. The pile-soil interface element is used. The influence of the combination type of piles on the deformation of bank slope and pile behaviour is analyzed. Different designs of a pile-supported pier are compared thoroughly. Calculation results show that the stresses and displacements of the pile are directly related to the distance from the bank slope and the direction of inclination. An inclined prop pile set in the rear platform would remarkably reduce the stresses of piles and the displacement of the pier. 相似文献
222.
Mai Yuanjian
Senior Engineer the th Harbour Engineering Bureau The Ministry of Communications of P. R. China Guangzhou 《中国海洋工程》1997,(2)
Based on statistics and analysis of the safety factor of unstable bank slopes,the relation be-tween safety level and reliability index of stability is studied and discussed,and then the elementary cali-brating calculation is carried out to the levels of safety and reliability for bank slope stability in the rangeof safety factors stipulated in existing China Technical Specifications for Port Engineering—FoundationPart(1987)and to those reached by some stable bank slopes already built.The results show that the relia-bility index β in the effective stress method is able to reach a high value of 2.4~4.1(mid-value 3.25),while the value of β in other three kinds of total stress method can just reach a lower value of 0.5~2.8(mid-value 1.65),which are in conformity with the engineering experience in China,and thus acceptable.Some suggestions are also given in this paper to the adoption of the value of β_0—objective reliability indexfor bank slope stability. 相似文献
223.
In order to suit the condition that the wave uplift is correlated with the horizontal wave load acting on a vertical breakwater, a generally used method for determining the reliability index β of the breakwater, i.e. the Hasofer-Lind method, is extended in a generalized stochastic space for correlative variables. The computational results for a caisson breakwater indicate that the value of β for the case of correlated variables is obviously smaller than that for the case of independent variables. 相似文献
224.
Yu Yuxiu Liu Shuxue
Professor State Key Laboratory of Coastal Offshore Engineering Dalian University of Technology 《中国海洋工程》1994,(1)
-The necessity of using irregular waves, especially multi- directional waves to conduct three-dimensional model tests for port engineering and the test method are described in this paper through an example of model test for a port. The test results show that a deep navigation channel has a large effect on the waves in front of the breakwater near the port entrance and on the wave condition in the port. 相似文献
225.
Simulation of the Whole Process of Ship-Bridge Collision 总被引:6,自引:0,他引:6
226.
Method to Determine Depositional Range of Sediment Transported from Multiple Sources in Water Area 总被引:1,自引:0,他引:1
Ying Qiang Jing Fei Ma Jin Rong
Engineer Nanjing Hydraulic Research Institute Nanjing Lecturer Nanjing College of Navigation Engineering Nanjing Assistant Engineer Nanjing Hydraulic Research Institute Nanjing 《中国海洋工程》1995,(3)
- The sediment from different sources have different content of the characteristic elements. According to the fuzzy mathematical theory, corresponding calculation and cluster analysis of each sediment sample are carried out, so the main courses of sediment transport in water area can be obtained. The characteristics of sediment from different sources are analysed. It is found that the sediment deposited of certain point in water area is due to the sources' contributions which can be calculated by the formula derived in this paper. Based on the distribution of the contribution values, the depositional range of sediment from each source can be determined. The depositional range in Huangmao Bay is determined as an example. 相似文献
227.
Cong Zheyan Ji Liangying
Senior Engineer Bohai Engineering & Design Company Shanghai Senior Engineer Shanghai Shipyard Shanghai 《中国海洋工程》1991,(1)
It is a new method of surveying leg spuds of self-elevating drilling platforms to lift them out of water with the help of additional middle guide blocks. Its main advantages in comparison with other methods normally used up to now are: less expensive, time saving, no need for specially designated water area, direct visual observation, good reliability and safety. The working principle has been presented with the example of two platforms "Bohai No. 8" and "Bohai No. 10", to which the method was used. Also a comprehensive comparison with other methods in technological and economical aspects is given in the paper. 相似文献
228.
Xie Wei Tang Xinming Engineer China Offshore Oil Development & Engineering Corporation Tianjin 《中国海洋工程》1993,(3)
The quasi-static analysis method introduced by API RP 2P is well known and accepted as a very useful mooring analysis method. In the early design stage, this method is widely used for preliminary analysis and mooring parameter selection. However, the quasi-static method of API RP 2P is developed for single-floating-body condition, i. e., only one floating body is considered in the computation procedure. Difficulties arise when it is used for the analysis of a CALM system, which is comprised of two floating bodies (tanker and buoy). This paper presents an analysis procedure for a two-floating-body system based on the quasi-static procedure of API RP 2P with some modifications reflecting special characteristics of the CALM system. Finally, the analysis results of a CALM system are given to illustrate the use of this procedure. 相似文献
229.
Lin Shaopei Zhang Zhongming Professor Civil Architectural Engineering Dept. Shanghai Jiao Tong University Shanghai Lecturer Civil Architectural Engineering Dept. Shanghai Jiao Tong University Shanghai 《中国海洋工程》1992,(1)
The present risk analysis model of engineering investment is built by fuzzy hierarchy approach under the assumption of maximizing the revenues of the project during its whole life cycle of operation. It can reasonably be expressed by a system evaluation analysis. As a matter of fact, the system, aimed by its system goal can be modelled by a set of factors, constitutively structured by certain links between them, to form a factorial network chart, which represents the essentials of the system behaviours, the nodes of which represent the factors concerned. The weight distribution between factors located at the same level can be determined by the eigen-value problem of a "pair comparison" relation matrix. The weight distribution of factors at each level is successively manipulated until the fuzzy synthetic risk assessment. As an example of risk analysis of engineering investment, a harbour construction project is presented for illustration. 相似文献
230.
Li Yucheng Professor Dept. of Civil Engineering Dalian University of Technology Dalian 《中国海洋工程》1992,(2)
Pierson- Moskowitz Spectrum, JONSWAP Spectrum as well as Bretschneider- Mitsuyasu Spectrum are used in this paper for analyzing the influence of wave energy directional spread on refraction of wave spectrum due to both current and topography of sea bed. The author's calculation indicates that such kind influence on the characteristic value of wave height as well as the average direction of wave energy propagation can not be ignored. 相似文献