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   3256篇
  免费   107篇
  国内免费   14篇
化学   2569篇
晶体学   48篇
力学   25篇
数学   111篇
物理学   624篇
  2023年   15篇
  2022年   28篇
  2021年   25篇
  2020年   32篇
  2019年   37篇
  2018年   30篇
  2017年   26篇
  2016年   59篇
  2015年   62篇
  2014年   73篇
  2013年   159篇
  2012年   184篇
  2011年   207篇
  2010年   126篇
  2009年   127篇
  2008年   183篇
  2007年   202篇
  2006年   208篇
  2005年   204篇
  2004年   152篇
  2003年   173篇
  2002年   145篇
  2001年   50篇
  2000年   43篇
  1999年   52篇
  1998年   23篇
  1997年   34篇
  1996年   48篇
  1995年   15篇
  1994年   24篇
  1993年   23篇
  1992年   40篇
  1991年   24篇
  1990年   29篇
  1989年   22篇
  1988年   28篇
  1987年   16篇
  1986年   23篇
  1985年   59篇
  1984年   54篇
  1983年   19篇
  1982年   41篇
  1981年   49篇
  1980年   45篇
  1979年   39篇
  1978年   25篇
  1977年   18篇
  1976年   20篇
  1975年   15篇
  1974年   13篇
排序方式: 共有3377条查询结果,搜索用时 0 毫秒
51.
Kenji Saijyou 《Applied Acoustics》2006,67(10):1031-1043
The relationship between the dominant mode of the submerged thin cylindrical shell and the flexural wave velocity is investigated. The natural frequency corresponding to the vibration mode is obtained as the solution of characteristic equation of thin cylindrical shell. However, it is difficult to estimate the dominant mode, especially if two or more vibration modes are involved. To estimate the dominant mode of a thin shell in vacuo, the concept of “modified bending stiffness” has been introduced. In this paper, the concept of modified bending stiffness is extended to estimate the dominant mode of a submerged thin cylindrical shell. The dominant mode of a submerged thin cylindrical shell is theoretically discriminated from the other mode based on the smallness of the modified bending stiffness of the submerged shell. The validity of our theory is confirmed by a good agreement between theoretical and experimental results on flexural wave velocity.  相似文献   
52.
High-temperature isothermal capacitance transient spectroscopy (H-ICTS) measurements were conducted to characterize near mid-gap defects, which are the origin of the memory effect in Ni/p-GaN Schottky contacts. A large single peak was detected only under the forward bias conditions. This indicates that the defects were located in the vicinity of the interface. The change of the peak height and position of the ICTS curves under various bias conditions were qualitatively interpreted by the distribution of the defects and the current flow effect.  相似文献   
53.
Entropy production per site in a (nonreversible) spin-flip process is studied. We give it a useful expression, from which a property stronger than affinity of the entropy production per site follows. Furthermore, quasi-invariance of nonequilibrium measures in the spin-flip processes is discussed via entropy production.  相似文献   
54.
An electrically addressable spatial light modulator is designed using nonlinear organic materials for optical information processing and display. One candidates for spatial light modulator (SLM) material is a nonlinear organic polymer of poly-methyl-methacrylate doped with disperse red 1. The measured electrooptic coefficient r33 is 2.9 pm/V at the wavelength of 633 nm. Resonator structure for a material is discussed with the goal of increasing electrooptic effects for SLM applications.  相似文献   
55.
Objective: To investigate the significance of intra-abdominal fat area (IAFA) on new onset of individual components of the metabolic syndrome: high blood pressure, dyslipidemia, or hyperglycemia. Methods: We conducted a longitudinal study using checkup data of a hospital from 1994 to 2010. Of 25,255 subjects, we examined 1,380 Japanese, who underwent computed tomography to measure IAFA and had no metabolic syndrome components at baseline. Results: During 3.6 years of the mean follow-up period, one of metabolic syndrome components occurred in 752 subjects. Of three components, high blood pressure was more prevalent. The multiple Cox regression analysis disclosed that IAFA is significantly associated with onset of metabolic syndrome components (HR: 1.05 per 10 cm2, 95%CI: 1.03–1.07). This finding was independent of BMI, and significant even in non-obese individuals with body mass index <25 kg/m2. Conclusions: MERLOT study demonstrates that IAFA is an independent predictor for new onset of individual components of the metabolic syndrome, even in non-obese healthy Japanese.  相似文献   
56.
News     
  相似文献   
57.
58.
59.
60.
Charmonia spectral functions at finite temperature are studied using QCD sum rules in combination with the maximum entropy method. This approach enables us to directly obtain the spectral function from the sum rules, without having to introduce any specific assumption about its functional form. As a result, it is found that while J/ψ and η(c) manifest themselves as significant peaks in the spectral function below the deconfinement temperature T(c), they quickly dissolve into the continuum and almost completely disappear at temperatures between 1.0T(c) and 1.1T(c).  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