首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   229篇
  免费   0篇
  国内免费   1篇
测绘学   12篇
大气科学   8篇
地球物理   46篇
地质学   35篇
海洋学   108篇
天文学   2篇
综合类   9篇
自然地理   10篇
  2016年   1篇
  2015年   1篇
  2014年   6篇
  2013年   8篇
  2012年   3篇
  2011年   8篇
  2010年   9篇
  2009年   7篇
  2008年   1篇
  2007年   10篇
  2006年   2篇
  2005年   4篇
  2004年   9篇
  2003年   1篇
  2001年   2篇
  2000年   11篇
  1999年   15篇
  1998年   18篇
  1997年   24篇
  1996年   10篇
  1995年   11篇
  1994年   7篇
  1993年   14篇
  1992年   11篇
  1991年   17篇
  1990年   3篇
  1989年   3篇
  1988年   3篇
  1987年   1篇
  1985年   2篇
  1984年   1篇
  1982年   1篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1967年   2篇
排序方式: 共有230条查询结果,搜索用时 15 毫秒
61.
The buckling propagation in marine pipelines is studied by means of the cylindrical shell model in this paper. Several parameters including geometrical parameter D/ T, L/ D, physical parameter E and σy are discussed. The computed results are compared with the available experimental data and other computed results, it is found that the present results are closer to the experimental results than other computed results.  相似文献   
62.
- Based on the Mohr-Coulomb failure principle and Rankine's theory, the laterally loaded pile ultimate resistance formulas of sand and soft clay proposed by Reese and Matlock respectively are discussed in this paper. The authors put forward the modified ultimate resistance formulas on the basis of which the ultimate resistance formula is developed for horizontally loaded pile in multi-layer soil in consideration of the effect of the overburden soil pressure on the calculation of soil layer. It is significant to the correct application of the ultimate resistance formulas in API and ZCS Rules into offshore engineering.  相似文献   
63.
Parh.  WE 《热带地理》1997,17(2):164-172
在热带条件下,不同种类岩石受到强烈的化学风化作用,并导致某些环境问题,香港在这方面提供了十分典型的例子。在香港,岩石风化厚度可达80min,普通成岩矿物长石和云母被转化为粘土矿物埃洛石和高岭石,风化岩密度一般降低40% ̄80%,埃洛石密度看来是亚稳定的,随年龄的增加而降低。在老于晚侏罗纪或早白垩纪的岩石中,还未临别出埃洛石。埃洛石、高岭石及其风化产物少含植物所需营养元素,且阳离子交换能力低,因而所  相似文献   
64.
Multipath influence on code range under static condition is described firstly in this paper, and the problem that to what extent the phase-aided smoothing can mitigate multipath interference is detailed. Some problems regarding smoothing and mitigation are discussed. Suggestions based on the analysis has been made.  相似文献   
65.
66.
I.INTRODUCTIONThefateofmanytraceheavymetalsinnaturalwatersis,toalargeextent,controlledbysorptionprocessesandthedynamicsoftheparticlesthemselves.Thepotentialinfluencesofenvironmentalvariablessuchastemperature,CaZ+,Na+andCI--,dissolvedorganiccarbonandPHvaluesontraceheavymetalpartitioninghavebeenwidelyinvestigated.Forexample,StumnandMorgan(1981)suggestthattheextentofsorptionvariespositivelywithtemperature.Itfollowsthatdecreasedsorptionmightbeexpectedatlowtemperatures,e.g.duringwintermont…  相似文献   
67.
PREFACE     
正The Abstracts of Chinese Geological Literature is edited and published by China Geological Library with an aim to provide bibliographic information to foreign geological circles on Chinese geological literature.The Abstracts is published in four numbers per annum.It gives reference s to more than one hundred Chinese periodicals and serials of  相似文献   
68.
A fatigue life estimation method for offshore structures under random stress response is studied in this paper. The method of broad band cumulative frequency number is used to determine the effect of band width of stress frequency spectra on fatigue. A formula of correction factor for fatigue under broad band stress spectra is suggested and compared with that given by P. H. Wirsching.  相似文献   
69.
The Wei- Liu water supplying submarine pipeline is at present the longest one of the kind in China. It is about 4 kilometers long from Weihai City to Liugong Island in Shandong province. It took only half a year to design and construct it. The project was of a high economic efficiency and some practical experiences were achieved. In this paper a general introduction to the design and construction of this pipeline is presented and such problems as the stability of the pipeline in very soft clay, design of curved slide for launching and estimation of dragging forces are expounded.  相似文献   
70.
- In this paper, by using the wave data from a few oceanographic observation stations in the coastal zone of the Yellow Sea, the East China Sea and the South China Sea, the long-term joint distribution of the one-tenth large (or significant) wave height with average period is studied. The statistical data demonstrate that the long- term distribution of the one- tenth wave height or average period fits the log-normal distribution, thus the joint distribution also fits the two-dimensional log-normal distribution. Then the conditional probability distribution of the average period is derived, and the range as well as the mode of the average wave period corresponding to a certain return period of wave height can be calculated easily.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号