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   92008篇
  免费   7852篇
  国内免费   8836篇
化学   31282篇
晶体学   438篇
力学   8188篇
综合类   1802篇
数学   37877篇
物理学   29109篇
  2024年   130篇
  2023年   749篇
  2022年   1601篇
  2021年   1761篇
  2020年   1830篇
  2019年   2114篇
  2018年   1807篇
  2017年   2220篇
  2016年   2515篇
  2015年   2177篇
  2014年   3433篇
  2013年   6087篇
  2012年   3896篇
  2011年   4519篇
  2010年   4001篇
  2009年   5453篇
  2008年   5845篇
  2007年   6036篇
  2006年   5498篇
  2005年   4714篇
  2004年   4264篇
  2003年   4267篇
  2002年   3888篇
  2001年   3221篇
  2000年   3155篇
  1999年   2833篇
  1998年   2671篇
  1997年   2169篇
  1996年   1939篇
  1995年   1691篇
  1994年   1577篇
  1993年   1313篇
  1992年   1266篇
  1991年   981篇
  1990年   818篇
  1989年   714篇
  1988年   632篇
  1987年   512篇
  1986年   415篇
  1985年   530篇
  1984年   490篇
  1983年   253篇
  1982年   422篇
  1981年   449篇
  1980年   335篇
  1979年   347篇
  1978年   264篇
  1977年   233篇
  1976年   177篇
  1974年   125篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Summary A review of the correlations between gravitational-wave detectors and particle detectors during SN1987A is given. The correlation between the Maryland and Rome g.w. detectors with the Mont Blanc neutrino detector is illustrated. This correlation extends during a period of one or two hours centred at 2∶45 UT of 23 February 1987, with the ?neutrino? signals delayed by (1.1±0.5) s and with a probability of the order of 10−5 to be accidental. Using the data obtained with the Kamiokande and IMB detectors, with the same statistical choices and procedures for the data analysis used previously, the above result is confirmed with a probability of the order of 10−3 or 10−4 that the additional correlation be accidental. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.  相似文献   
992.
本文提出一种利用材料Hugoniot数据研究高压下离子晶体中微观离子状态及其离子间排斥作用势的新方法。对氢化锂晶体进行研究时,我们得到Li~+和H~-离子之间排斥作用势函数,结果表明文献〔1〕中提出的离子压缩效应具有客观性。  相似文献   
993.
The management of voice disorders may follow one of four approaches: surgical, pharmacological, technical aid, and/or voice therapy. The latter approach offers a wide variety of techniques, each based on certain theoretical beliefs. One of these techniques is the Smith Accent Method. The principles and goals of the Accent Method are presented. The results of its application are discussed. This technique proved effective for cases of functional voice disorders, vocal nodules, and some degrees of vocal fold paralysis.  相似文献   
994.
We shall prove here that any binary relation on a base E with cardinality n > 6 is reconstructible from its restrictions of cardinality 2, 3, 4 and (n - 1). This proof needs results of part I of this paper where we characterize any pair of relations R, R' which are 2-, 3- and 4-hypomorphic. As a corollary we obtain that any binary relation is (n - 4)-reconstructible (when n > 9).  相似文献   
995.
Summary We report on the development of an adaptive optimum filter for processing the data of a resonant bar gravitational-wave detector. This filter, based on the matched-filter theory, is adaptive in the sense that the function it realizes is derived from the actual noise spectrum of the data being analysed (instead from an idealized model of the noise). Its implementation is mostly based on frequency domain techniques. We also report on the application of the new filter to the data of the cryogenic antenna Explorer of the Rome group, with particular reference to the comparison between its performance and that of an otpimum filter with fixed values of the parameters.  相似文献   
996.
This paper obtains some fixed point theorems of semidifferentiable semmicompacl l-set-contraction maps, which extend some known results in [1, 2, 4, 5, 7].  相似文献   
997.
Based on numerical calculations, the experiments on mixing at the interface of gases are analyzed. Single-mode and random disturbances of the interface and superposition of random disturbances onto long-wave perturbations are considered. Possible reasons for the higher value of the mixing constant obtained in the experiments are discussed.  相似文献   
998.
利用K-泛函研究了修正的Baskakov型算子的Stechin-Marchaud型不等式,由此不等式,我们得到了关于ω2φλ的逆结果.  相似文献   
999.
电磁继电器触点参数的测试   总被引:1,自引:0,他引:1  
本文介绍了电磁继电器触点电参数的测试方法,包括接触电阻、绝缘电阻参数测试。  相似文献   
1000.
We study the system of nonlinear differential equations which expresses the constancy of the algebraic invariants of the Jacobian matrix for smooth vector fields in three-dimensional space. This system is equivalent to the equations of gas dynamics which describe the barochronous motions of a gas (the pressure and density depend only on the time). We present the results of computation of the admissible local Lie group and construction of the general solution of the system. We mention a few new problems that arise here.  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