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   118182篇
  免费   6049篇
  国内免费   5790篇
化学   56448篇
晶体学   1332篇
力学   5589篇
综合类   326篇
数学   11858篇
物理学   33897篇
综合类   20571篇
  2023年   971篇
  2022年   2096篇
  2021年   2604篇
  2020年   2652篇
  2019年   2686篇
  2018年   3129篇
  2017年   3109篇
  2016年   3792篇
  2015年   2978篇
  2014年   4277篇
  2013年   5690篇
  2012年   5881篇
  2011年   6221篇
  2010年   5039篇
  2009年   5128篇
  2008年   5486篇
  2007年   5172篇
  2006年   4655篇
  2005年   4239篇
  2004年   3641篇
  2003年   3348篇
  2002年   3774篇
  2001年   3511篇
  2000年   2660篇
  1999年   2439篇
  1998年   2134篇
  1997年   1863篇
  1996年   1780篇
  1995年   1545篇
  1994年   1547篇
  1993年   1453篇
  1992年   1356篇
  1991年   1438篇
  1990年   1394篇
  1989年   1269篇
  1988年   1113篇
  1987年   1057篇
  1986年   961篇
  1985年   944篇
  1984年   921篇
  1983年   824篇
  1982年   801篇
  1979年   801篇
  1978年   812篇
  1977年   806篇
  1976年   919篇
  1975年   812篇
  1974年   845篇
  1973年   847篇
  1972年   752篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
The electrochemical behavior of gatifloxacin (GTFX) and its interaction with natural calf thymus DNA (ctDNA) is investigated by differential pulse voltammetry (DPV) on a carbon paraffined electrode. According to the suggested electrochemical equation, a binding constant of 1.7058 x 10(5) (mol L(-1))(-1) and binding sizes s = 3.09 (base pairs) of GTFX with ctDNA are obtained by nonlinear fit analysis of electrochemical data. The results demonstrate that GTFX has the properties of an intercalative binder.  相似文献   
103.
The complexing properties of cellulose complexite with respect to copper(II) ions in water-1,4-dioxane (DO) mixtures are determined. The stoichiometry and stability constants of copper(II) complexes with the hydroxamic groups of the polymer are determined. The equilibrium speciation diagrams for the complexes at pH 2.0–6.0 are plotted; stereochemical configurations are suggested. The effect of the solvation parameters of the complexite on complex formation is analyzed.  相似文献   
104.
A complex numerical and experimental investigation of burner devices for a reburning of the anode gas of aluminum production was carried out. The chosen mathematical model of the processes of aerodynamics, heat exchange, and gas burning was identified and adapted on the basis of data of real-scale measurements. Basing on computational experiments the optimization of the design of elements of the system for anode gas detoxication and transport was carried out. A new system was proposed and tested for reburning the anode gases of electrolysis production, which consists of an improved burner device and a dust-sedimenting chamber with a possibility of regulating the amount of gas suction.  相似文献   
105.
We propose a general idea of obtaining different chains of coupled oscillators with chaotic buffering. As examples, we consider chains of diffusively coupled generalized cubic Schrödinger equations and nonlinear telegraph equations. We also give examples of systems that have an infinite-dimensional chaotic attractor.  相似文献   
106.
Depolymerization of chitin and chitosan in the course of deacetylation in an alkaline medium was studied, and the influence exerted on the process by the nature and concentration of the alkali (NaOH, KOH) and salts (NaCl, NaI, KI) was examined.  相似文献   
107.
It is suggested to take as pH of the precipitation onset of metal hydroxides the pH at which 10% of the initial amount of metal ions has precipitated. An equation for calculating this quantity is presented.  相似文献   
108.
109.
A nonrelativistic deuteron wave function involving the D-wave state and having a correct asymptotic behavior is constructed on the basis of the experimentally measured deuteron charge form factor G C(q) and deuteron structure function A(q). The differential cross section for elastic deuteron-nucleus scattering is calculated by using this wave function and is found to agree with experimental data at an energy of 110 MeV. Integrated cross sections for various processes involving deuteron-nucleus interactions are also calculated. The distribution in the emission angle of the center of mass of the neutron-proton system produced in the diffractive dissociation of 110-MeV deuterons in the field of 208Pb nuclei is obtained.  相似文献   
110.
Kinetic features of radical polymerization of styrene initiated by tert-butyl perbenzoate in the presence of tris(N,N-dimethyldithiocarbamato)cobalt(III) (CoL3) and its adduct with iodine (CoL3 · 2I2) were studied. The optimal concentration ratios of the activators and tert-butyl perbenzoate, providing fast styrene polymerization at 338–368 K, were determined.  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