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   1197篇
  免费   80篇
  国内免费   173篇
化学   426篇
晶体学   24篇
力学   37篇
综合类   10篇
数学   41篇
物理学   912篇
  2024年   14篇
  2023年   131篇
  2022年   43篇
  2021年   50篇
  2020年   42篇
  2019年   43篇
  2018年   31篇
  2017年   56篇
  2016年   43篇
  2015年   46篇
  2014年   73篇
  2013年   63篇
  2012年   55篇
  2011年   104篇
  2010年   89篇
  2009年   64篇
  2008年   78篇
  2007年   44篇
  2006年   50篇
  2005年   43篇
  2004年   34篇
  2003年   26篇
  2002年   46篇
  2001年   23篇
  2000年   32篇
  1999年   15篇
  1998年   12篇
  1997年   14篇
  1996年   11篇
  1995年   8篇
  1994年   6篇
  1993年   4篇
  1992年   11篇
  1991年   3篇
  1990年   6篇
  1989年   4篇
  1988年   8篇
  1986年   2篇
  1985年   5篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1980年   2篇
  1979年   5篇
  1978年   1篇
  1976年   1篇
  1975年   1篇
  1974年   3篇
  1973年   1篇
排序方式: 共有1450条查询结果,搜索用时 15 毫秒
111.
Amitava Datta 《Pramana》1993,40(6):L503-L509
It is argued with the help of an illustrative model, that the inter species hierarchy among the fermion masses and the quark mixing angles can be accommodated naturally in the standard model with (approximate) flavor democracy provided there are three exactly massless neutrinos and four families of sequential quark-leptons with all members of the fourth family having roughly equal masses. The special problem of light neutrino masses (if any) and possible solutions are also discussed.  相似文献   
112.
粲夸克偶素强衰变之谜   总被引:1,自引:0,他引:1  
顾以藩 《物理》1996,25(2):65-67
北京正负电子对撞机的最新实验研究结果在高灵敏度水平上展出了粲夸克偶素物理中的强衰变之谜,新反常衰变道的发现突破了这个谜的原有图像,对理论提出了新的挑战。  相似文献   
113.
This report summarises the activities of the working group on ‘Physics beyond the Standard Model’. The results of investigations in incorporatingR-parity in grand unification, the possibility of a light charged Higgs boson in extension of MSSM and radiative generation of neutral vector boson self-couplings within the MSSM are described. Also given is an account of activities in neutrino physics, namely a proposal for a study of the atmospheric muon anomaly in deep underground mines, a field theoretic study of neutrino oscillations and a mechanism to generate appropriate masses of three active plus one sterile neutrino species.  相似文献   
114.
Summary In this note we describe the image acquisition system realized as a part of an experiment designed to record high-spectral-resolution solar images in the visible part of the spectrum. The system is based on a Charge Coupled Device Thomson THX31159. The electronics for driving the sensor and for the amplification and conditioning of the video signal has been designed and built in the laboratory, while a VME-bus-based computer has been used for the timing of operations, for the signal A/D conversion and for image presentation and storage. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.  相似文献   
115.
We construct a model where neutrino Majorana masses are small and hierarchical but where neutrinoless double beta decay occurs at an observable rate potentially detectable by present day experiments.  相似文献   
116.
The view factor (angle factor) for a differential inclined plane in the case of a radiating source of radially Gaussian intensity is considered. This information is useful for modelling of solar radiation in certain applications. The view factor is expressed in terms of two integrals, one of which is obtained in closed form in terms of special functions, and the other is approximated. A compact estimate for the view factor is presented which is suitable for machine computation. While the relative error associated with the final estimate is typically less than 0.01%, and in all cases, less than 0.2%, the method is easily extended to yield even greater accuracy.  相似文献   
117.
Summary Solar-wind data, as obtained in the near-Earth space, have been re-examined for the period 1964 to 1987. For each month, the maximum and minimum hourly values of the solar-wind bulk speed together with those for the interplanetary magnetic-field intensity have been selected. They are reported in a tabular form (available as readable ASCII text files on DOS-formatted floppy disks) to ease off further studies in the framework of the Solar-Terrestrial System.  相似文献   
118.
继承异常用来描述在并发面向对象语言中继承与并发的冲突.对继承异常做了系统的分析,给出一种新的分类.提出在一并发对象中将同步部分与顺序部分分离,生成两个对象,通过将同步代码放入一单独对象,将继承过程分为顺序部分和同步部分,这种分离大大地减少了继承异常的发生.  相似文献   
119.
Dimuon events induced by charm-quark productions from neutrino deep inelastic scattering (DIS) processes have been studied in traditional DIS experiments for decades. The recent progress in neutrino telescopes makes it possible to search for such dimuon events at energies far beyond the laboratory scale. In this study, we construct a simulation framework to calculate yields and distributions of dimuon signals in an IceCube-like km3 scale neutrino telescope. Owing to the experimental limitation in the resolution of double-track lateral distance, only dimuons produced outside the detector volume are considered. Detailed information about simulation results for a 10-year exposure is presented. As an earlier paper[Physical Review D 105, 093005 (2022)] and ours report on a similar situation, we use that paper as a baseline to conduct comparisons. We then estimate the impacts of different calculation methods of muon energy losses. Finally, we study the experimental potential of dimuon searches under the hypothesis of single-muon background only. Our results based on a simplified double-track reconstruction indicate a moderate sensitivity, especially with the ORCA configuration. Further developments on both the reconstruction algorithm and possible detector designs are thus required and are under investigation.  相似文献   
120.
A PEC cell with nanostructured BiVO4 photoelectrode film presents outstanding azo dye degradation and simultaneous H2 production performance.  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