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   655898篇
  免费   9740篇
  国内免费   6248篇
化学   324719篇
晶体学   8979篇
力学   35970篇
综合类   339篇
数学   105986篇
物理学   195893篇
  2021年   6554篇
  2020年   7129篇
  2019年   7898篇
  2018年   19576篇
  2017年   19286篇
  2016年   19187篇
  2015年   8750篇
  2014年   13055篇
  2013年   27024篇
  2012年   25282篇
  2011年   34841篇
  2010年   24226篇
  2009年   24480篇
  2008年   29453篇
  2007年   30939篇
  2006年   21206篇
  2005年   19908篇
  2004年   18685篇
  2003年   17374篇
  2002年   16487篇
  2001年   16461篇
  2000年   12819篇
  1999年   9944篇
  1998年   8746篇
  1997年   8392篇
  1996年   7942篇
  1995年   7083篇
  1994年   7089篇
  1993年   6796篇
  1992年   7040篇
  1991年   7511篇
  1990年   7221篇
  1989年   7057篇
  1988年   6804篇
  1987年   6574篇
  1986年   6311篇
  1985年   7880篇
  1984年   8201篇
  1983年   6928篇
  1982年   7197篇
  1981年   6668篇
  1980年   6337篇
  1979年   6887篇
  1978年   7120篇
  1977年   6993篇
  1976年   7019篇
  1975年   6694篇
  1974年   6520篇
  1973年   6860篇
  1972年   5077篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Translated from Chislennye Metody Resheniya Obratnykh Zadach Matematicheskoi Fiziki, pp. 119–127.  相似文献   
92.
The proof of the existence of classical solutions is given for the Painlevé type nonlinear ordinary differential equations. The solutions have asymptotic formulas, which can be obtained by the isomonodromic deformation method.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova, Vol. 179, pp. 101–109, 1989.  相似文献   
93.
The finite-size corrections, central chargesc, and scaling dimensionsx of tricritical hard squares and critical hard hexagons are calculated analytically. This is achieved by solving the special functional equation or inversion identity satisfied by the commuting row transfer matrices of these lattice models at criticality. The results are expressed in terms of Rogers dilogarithms. For tricritical hard squares we obtainc=7/10,x=3/40, 1/5, 7/8, 6/5 and for hard hexagons we obtainc=4/5,x=2/15, 4/5, 17/15, 4/3, 9/5, in accord with the predictions of conformal and modular invariance.  相似文献   
94.
Exact closed-form solutions are exhibited for the Hopf equation for stationary incompressible 3D Navier-Stokes flow, for the cases of homogeneous forced flow (including a solution with depleted nonlinearity) and inhomogeneous flow with arbitrary boundary conditions. This provides an exact method for computing two- and higher-point moments, given the mean flow.  相似文献   
95.
成功地在六路高功率Nd玻璃激光装置上建立了2660紫外激光探针和适合紫外波段的Normaski干涉仪,首次将可见波长的连续激光应用于紫外干涉仪中靶成像调整和光路准直。利用该紫外光干涉仪,在铜柱状靶(φ500μm)上测量了厚等离子体中高达0.6n。的电子密度。  相似文献   
96.
V. A. Steklov Mathematics Institute, USSR Academy of Sciences. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 79, No. 3, pp. 347–358, June, 1989.  相似文献   
97.
Courses which teach discrete-event simulation are based on many different simulation languages. The requirements for a language to support teaching simulation are discussed. In particular, it is recommended that such languages separate into distinct modules those aspects of simulation which are taught as separate topics. Implementation of the separation is discussed. The SEESIM language, developed as a teaching aid, is described, and examples of its use are given. Straightforward use of SEESIM can be learned quickly, yet the language provides facilities for a staged introduction to advanced concepts of simulation.  相似文献   
98.
The main notions and results which are necessary for finding higher symmetries and conservation laws for general systems of partial differential equations are given. These constitute the starting point for the subsequent papers of this volume. Some problems are also discussed.  相似文献   
99.
Yu V Sharvin 《Pramana》1987,28(5):592-592
Investigation of the galvanomagnetic properties of disordered metals in weak magnetic fields [r(H)?l, wherer(H) is the electron trajectory radius andl, the electron free path], proved to be one of the effective experimental methods of studying disordered metals. The phase difference between the interfering electron waves is affected by the presence of magnetic flux in the sample. One of the observable effects is the oscillatory magnetoresistanceK(H) of multiconnected samples predicted by Altshuleret al (1981). The period ofK(H) oscillations for the hollow cylinders, networks or chains with orifices cross-sections areasS isΔH=φ 0/2S [whereφ 0=hc/e]. The amplitude and the phase of the oscillations depend on the spin orbit interaction, the intensity of superconductive fluctuation etc. It should be noted that in small “mesoscopic” single loops the oscillations with the periodΔH?φ 0/S were also observed recently (see also Altshuleret al 1987 included in this issue).  相似文献   
100.
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