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   482620篇
  免费   3408篇
  国内免费   1097篇
化学   236661篇
晶体学   7607篇
力学   24043篇
综合类   12篇
数学   68610篇
物理学   150192篇
  2020年   3206篇
  2019年   3576篇
  2018年   11860篇
  2017年   12585篇
  2016年   10436篇
  2015年   4880篇
  2014年   6927篇
  2013年   17200篇
  2012年   16212篇
  2011年   25366篇
  2010年   16899篇
  2009年   16741篇
  2008年   22918篇
  2007年   25832篇
  2006年   13863篇
  2005年   17485篇
  2004年   14083篇
  2003年   13154篇
  2002年   11304篇
  2001年   11499篇
  2000年   8983篇
  1999年   6760篇
  1998年   5838篇
  1997年   5722篇
  1996年   5526篇
  1995年   5142篇
  1994年   5220篇
  1993年   4887篇
  1992年   5533篇
  1991年   5512篇
  1990年   5387篇
  1989年   5230篇
  1988年   5285篇
  1987年   5171篇
  1986年   4938篇
  1985年   6493篇
  1984年   6793篇
  1983年   5864篇
  1982年   6007篇
  1981年   5817篇
  1980年   5750篇
  1979年   5864篇
  1978年   6205篇
  1977年   6012篇
  1976年   6144篇
  1975年   5752篇
  1974年   5776篇
  1973年   6073篇
  1972年   4198篇
  1971年   3452篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Journal of Structural Chemistry - An analysis is presented for the results obtained in the studies initiated by A. E. Shvelashivili, Corresponding Member, Academy of Sciences of Georgia, and...  相似文献   
72.
73.
The structure, chemical composition, and magnetic properties of electrochemically deposited nanocrystalline Co-Ni-Fe films were investigated using a number of techniques. A high saturation magnetic induction up to B s = 21 kG was attained. An enhancement of the saturation magnetization compared to the ideal anticipated one was revealed, which correlated with the nonlinear behavior of the structural phase composition and lattice parameters with the change of the composition. The text was submitted by the authors in English.  相似文献   
74.
Methods for phase stabilization of ammonium nitrate were sought for in order to considerably expand the application area of this oxidizing agent in various-purpose self-combustible formulations, including that in a new generation of gas-generating formulations for automobile air bags. New methods for stabilization of ammonium nitrate were studied and, in particular, a search was made for organic compounds that can stabilize ammonium nitrate even at their low content. The mechanism of phase state stabilization of ammonium nitrate by compounds of this kind was examined.  相似文献   
75.
Kinetic, sorption and selectivity properties of commercial adsorbents are improved by adding petroleum residues (tar asphaltene concentrates) 13% of whole mass. Obtained adsorbents can be used for selective extraction of nobel metals from multicomponent polymetallic solutions of heavy metals and fro sewages purification for removing arsenic.  相似文献   
76.
Demixing during film casting of blends of polystyrene, polymethylmethacrylate, and a symmetric diblock copolymer of styrene and methylmethacrylate is discussed. The concentration fluctuations in the homogeneous solutions were calculated in mean field approximation. The structures in the homogeneous and demixed solutions and in the dry films were measured by small-angle x-ray scattering, and the morphologies of the dry films were characterized by transmission electron microscopy. The structure of the dry blends is evidently already pre-formed in solution.  相似文献   
77.
78.
The lidar equation for the vibrational backscattering of neodymium laser radiation and its harmonics by hydrogen molecules is solved numerically. Inclined paths in the atmosphere are investigated with the aim of selecting the transmitter wavelength for detecting the lowest concentrations of hydrogen. Zh. Tekh. Fiz. 68, 20–22 (January 1998)  相似文献   
79.
The electrostatic problem for a thin, unclosed spherical shell and a torus is reduced to paired summation equations in the Legendre polynomials by means of formulas relating the spherical and toroidal harmonic functions. The paired equations are transformed to a Fredholm integral equation of the second kind. Formulas are obtained for computing the charges of the conductors in the form of a series in a small parameter. The capacitance is computed for certain geometrical parameters of the conductors. Zh. Tekh. Fiz. 68, 1–6 (July 1998)  相似文献   
80.
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