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   2508篇
  免费   62篇
  国内免费   11篇
化学   1828篇
晶体学   21篇
力学   49篇
数学   203篇
物理学   480篇
  2023年   11篇
  2022年   23篇
  2021年   31篇
  2020年   40篇
  2019年   24篇
  2018年   17篇
  2017年   19篇
  2016年   41篇
  2015年   60篇
  2014年   59篇
  2013年   128篇
  2012年   159篇
  2011年   172篇
  2010年   99篇
  2009年   83篇
  2008年   156篇
  2007年   143篇
  2006年   139篇
  2005年   146篇
  2004年   105篇
  2003年   95篇
  2002年   74篇
  2001年   31篇
  2000年   38篇
  1999年   28篇
  1998年   25篇
  1997年   23篇
  1996年   37篇
  1995年   28篇
  1994年   26篇
  1993年   45篇
  1992年   22篇
  1991年   13篇
  1990年   17篇
  1989年   16篇
  1988年   21篇
  1987年   23篇
  1986年   15篇
  1985年   26篇
  1984年   17篇
  1983年   18篇
  1982年   21篇
  1981年   18篇
  1980年   14篇
  1979年   27篇
  1978年   15篇
  1977年   15篇
  1976年   12篇
  1974年   10篇
  1973年   16篇
排序方式: 共有2581条查询结果,搜索用时 15 毫秒
1.
Homogenous amphiphilic crosslinked polymer films comprising of poly(ethylene oxide) and polysiloxane were synthesized utilizing thiol‐ene “ click ” photochemistry. A systematic variation in polymer composition was Carried out to obtain high quality films with varied amount of siloxane and poly(ethylene oxide). These films showed improved gas separation performance with high gas permeabilities with good CO2/N2 selectivity. Furthermore, the resulting films were also tested for its biocompatibility, as a carrier media which allow human adult mesenchymal stem cells to retain their capacity for osteoblastic differentiation after transplantation. The obtained crosslinked films were characterized using differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, FTIR, Raman‐IR , and small angle X‐ray scattering. The synthesis ease and commercial availability of the starting materials suggests that these new crosslinked polymer networks could find applications in wide range of applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1548–1557  相似文献   
2.
Suppose there exists a global solution u to the incompressible Navier–Stokes equations, such that u∈Ct(H?1/2). We prove that its H?1/2 norm goes to 0 at infinity. We next use this fact to control the L2t(H?3/2) norm of u, and finally we prove that such a solution is stable. To cite this article: I. Gallagher et al., C. R. Acad. Sci. Paris, Ser. I 334 (2002) 289–292.  相似文献   
3.
4.
5.
We present in this paper a domain decomposition method to treat faults in geological basin modeling. The particularity of this model is that the faults whose widths are very small in comparison with the basin size, are not characterized as subdomains any more but as interfaces between sedimentary blocks. The originality of this work lies in the formulation of this new fault model and in the definition and the computation of the interface conditions between the subdomains. To cite this article: E. Flauraud et al., C. R. Mecanique 331 (2003).  相似文献   
6.
A method for the production of transparent carbon nanotube networks (CNTNs) over transparent substrates was developed. In this method, CNTNs were grown directly in the target surface by applying the catalyst in specific zones of the substrate through lithographic techniques. The networks can be also transferred from the original substrate to other surfaces. The newly grown carbon nanotubes have a very high aspect ratio (>50000). Thus far, networks with an optical transmittance of 94% at 550 nm and a surface resistivity of 3.6 kΩ/sq have been produced. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
7.
8.
The breakup of suspended, agglomerated submicron particles was studied by exposing the aerosol to weak shock waves of varying strength under conditions 400 ms?1?v?880 ms?1. A newly developed laser light-scattering diagnostic employing a top hat laser profile was used to size the particles passing through a very small scattering volume. By Comparing the optically measured particle size in front of and behind shock waves, the breakup of agglomerated particles could be clearly identified. The experiments indicate that the aerodynamic forces behind an incident shock overcome the particle binding force resulting in disintegration of the submicron agglomerates. The results are presented in form of a modified Weber number.  相似文献   
9.
We investigate the self-energy of one electron coupled to a quantized radiation field by extending the ideas developed in Hainzl (Ann. H. Poincaré, in press). We fix an arbitrary cut-off parameter Λ and recover the α2-term of the self-energy, where α is the coupling parameter representing the fine structure constant. Thereby we develop a method which allows to expand the self-energy up to any power of α. This implies that perturbation theory in α is correct if Λ is fix. As an immediate consequence we obtain enhanced binding for electrons.  相似文献   
10.
A novel approach to H-phosphonates from hypophosphorous acid using a transfer hydrogenation process was developed. This method is atom-economical, environmentally friendly, catalytic, and efficient, leading easily to H-phosphonate monoesters or ammonium salt in moderate to good yields.  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