全文获取类型
收费全文 | 758篇 |
免费 | 63篇 |
国内免费 | 229篇 |
专业分类
化学 | 679篇 |
晶体学 | 21篇 |
力学 | 106篇 |
综合类 | 17篇 |
数学 | 6篇 |
物理学 | 221篇 |
出版年
2024年 | 5篇 |
2023年 | 15篇 |
2022年 | 20篇 |
2021年 | 24篇 |
2020年 | 19篇 |
2019年 | 22篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 20篇 |
2015年 | 21篇 |
2014年 | 75篇 |
2013年 | 47篇 |
2012年 | 45篇 |
2011年 | 44篇 |
2010年 | 49篇 |
2009年 | 58篇 |
2008年 | 42篇 |
2007年 | 44篇 |
2006年 | 53篇 |
2005年 | 50篇 |
2004年 | 32篇 |
2003年 | 28篇 |
2002年 | 31篇 |
2001年 | 41篇 |
2000年 | 41篇 |
1999年 | 39篇 |
1998年 | 33篇 |
1997年 | 28篇 |
1996年 | 19篇 |
1995年 | 23篇 |
1994年 | 24篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1987年 | 1篇 |
排序方式: 共有1050条查询结果,搜索用时 15 毫秒
101.
Some hydrodynamic aspects of 3-phase inverse fluidized bed 总被引:2,自引:0,他引:2
Krishna S.V.S.R. Bandaru D.V.S. Murthy K. Krishnaiah 《中国颗粒学报》2007,5(5):351-356
Hydrodynamics of 3-phase inverse fluidized bed is studied experimentally using low density particles for different liquid and gas velocities. The hydrodynamic characteristics studied include pressure drop, minimum liquid and gas fluidization velocities and phase holdups. The minimum liquid fluidization velocity determined using the bed pressure gradient, decreases with increase in gas velocity. The axial profiles of phase holdups shows that the liquid holdup increases along the bed height, whereas the solid holdup decreases down the bed. However, the gas holdup is almost uniform in the bed. 相似文献
102.
103.
104.
105.
Similarly to but quite different from the xenon poisoning effects resulting from fission-produced iodine during the restart-up process of a fission reactor, we introduce a completely new concept of the tritium burn-up depth and tritium break-even time in the fusion energy research area. To show what the least required amount of tritium storage is used to start up a fusion reactor and how long a time the fusion reactor needs to be operated for achieving the tritium break-even during the initial start-up phase due to the finite tritium breeding time that is dependent on the tritium breeder, specific structure of breeding zone, layout of coolant flow pipe, tritium recovery scheme, extraction process, the tritium retention of reactor components, unrecoverable tritium fraction in breeder, leakage to the inertial gas container, and the natural decay etc., we describe this new phenomenon and answer this problem by setting up and by solving a set of equations, which express a dynamic subsystem model of the tritium inventory evolution in a fusion experimental breeder (FEB). It is found that the tritium burn-up depth is 317g and the tritium break-even time is approximately 240 full power days for FEB designed detail configuration and it is also found that after one-year operation, the tritium storage reaches 1.18kg that is more than the least required amount of tritium storage to start up three of FEB-like fusion reactors. 相似文献
106.
107.
热烟气启动流化床的数学模型 总被引:2,自引:0,他引:2
1引言在流化床锅炉能够正常运行之前,必须进行点火操作,把惰性床料流化加热到足够高的温度,以使燃料能够开始燃烧。用高温热烟气经由布风板加热床层,传热效率较高,易于实现自动控制,能够明显缩短启动时间,减少辅助燃料消耗,目前国外普遍采用这种方法山。在我国第一台中试PFBC锅炉的启动中,就将采用热烟气启动的方式。为了对热烟气启动增压流化床进行模拟研究,提出了一种热烟气启动流化床的简化模型二本文提出的简化模型,考虑了扬析、磨损等因素,力求物理概念正确、简单实用、功能强;特别是借鉴对于间隙扬析过程的处理方法,… 相似文献
108.
LipingMa WeixingHuang YanfuShi HuaruiYu JingxuZhu 《中国颗粒学报》2005,3(1):80-83
In this paper, multifractal analysis together with wavelet transform modulus maxima (WTMM) method is used to analyze the fluctuating signals of circulating fluidized bed (CFB). Singularity spectrum shows that the gas-particle flow in CFB has multifractal character. Motion behavior of the particle-fluid system of CFB can be described by singularity spectrum. Intermittency index can be used to determine the transition of flow regime from fast fluidization to pneumatic conveying. 相似文献
109.
110.
YUAN Tao FENG Kaiming 《核工业西南物理研究院年报(英文版)》2005,(1):95-97
The helium cooled solid breeder blanket that represents the main stream in relevant blanket concepts. It is considered as one of the main options for the fusion reactor. This concept have advantage as follows: ( 1 ) structure simpleness and stability, ( 2 ) no effect of MHD, ( 3 ) a good compatibility in different materials. 相似文献