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   1274篇
  免费   170篇
  国内免费   137篇
化学   892篇
晶体学   10篇
力学   84篇
综合类   9篇
数学   161篇
物理学   425篇
  2024年   7篇
  2023年   35篇
  2022年   59篇
  2021年   62篇
  2020年   73篇
  2019年   56篇
  2018年   55篇
  2017年   55篇
  2016年   60篇
  2015年   53篇
  2014年   78篇
  2013年   98篇
  2012年   116篇
  2011年   105篇
  2010年   68篇
  2009年   56篇
  2008年   67篇
  2007年   71篇
  2006年   64篇
  2005年   54篇
  2004年   25篇
  2003年   30篇
  2002年   22篇
  2001年   26篇
  2000年   27篇
  1999年   21篇
  1998年   13篇
  1997年   12篇
  1996年   23篇
  1995年   10篇
  1994年   16篇
  1993年   8篇
  1992年   17篇
  1991年   10篇
  1990年   3篇
  1989年   2篇
  1988年   3篇
  1987年   6篇
  1986年   7篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1970年   1篇
  1965年   1篇
  1958年   1篇
排序方式: 共有1581条查询结果,搜索用时 109 毫秒
101.
102.
合成了一种新型的导电配位型化合物(FeCp2)0.65FNi(C3S7)2].通过元素分析(EA),电感耦合等离子体原子发射光谱(ICP—AES),核磁共振(^1HNMR),紫外光谱(UV)对该化合物进行了表征。  相似文献   
103.
Huo  Donghui  Wang  Hongzhao  Qin  Zijian  Tian  Yujia  Yan  Aixia 《Molecular diversity》2022,26(3):1715-1730
Molecular Diversity - Epidermal growth factor receptor (EGFR) has received widespread attention because it is an important target for anticancer drug design. Mutations in the EGFR, especially the...  相似文献   
104.
105.
A pulsed time-of-flight (TOF) laser rangefinder with a pulsed laser diode and an avalanche photo diode (APD) receiver is constructed and tested. Trigged by an avalanche transistor, the laser diode can emit a periodic pulse with rise time of ~2 ns. A new structure with auto gain control (AGC) circuits both in the pre-amplifier and the post-amplifier is presented. Through this technology, not only the dynamic range of the receiver is extended, but also the walk error of timing discriminators is reduced. Large measurement range from 5 m to 500 m is achieved without any cooperative target. The single-shot precision is 3 cm for the weakest signal. Compared with previous laser rangefinders, the complexity of this system is greatly simplified.  相似文献   
106.
High-resolution scanning tunneling microscopy (STM) and temperature-programmed desorption (TPD) were used to study the interaction of O2 with reduced TiO2(110)–(1 × 1) crystals. STM is the technique of choice to unravel the relation between vacancy and non-vacancy assisted O2 dissociation channels as a function of temperature. It is revealed that the vacancy-assisted, first O2 dissociation channel is preferred at low temperature (~ 120 K), whereas the non-vacancy assisted, second O2 dissociation channel operates at temperatures higher than 150 K–180 K. Based on the STM results on the two dissociative O2 interaction channels and the TPD data, a new comprehensive model of the O2 chemisorption on reduced TiO2(110) is proposed. The model explains the relations between the two dissociative and the molecular O2 interaction channels. The experimental data are interpreted by considering the available charge in the near-surface region of reduced TiO2(110) crystals, the kinetics of the two O2 dissociation channels as well as the kinetics of the diffusion and reaction of Ti interstitials.  相似文献   
107.
彩虹全息术的发生与发展是与狭缝的引入与演变相关的。本文试图用一个简明的表格形式把迄今为止存在着的各种彩虹全息图及其变化状态做一个形象化的小结。  相似文献   
108.
The quality of DOSY NMR data can be improved by careful pre-processing techniques. Baseline drift, peak shift, and phase shift commonly exist in real-world DOSY NMR data. These phenomena seriously hinder the data analysis and should be removed as much as possible. In this paper, a series of preprocessing operations are proposed so that the subsequent multivariate curve resolution can yield optimal results. First, the baseline is corrected according to a method by Golotvin and Williams. Next, frequency and phase shift are removed by a new combination of reference deconvolution (FIDDLE), and a method presented by Witjes et al. that can correct several spectra simultaneously. The corrected data are analysed by the combination of multivariate curve resolution with non-linear least square regression (MCR-NLR). The MCR-NLR method turns out to be more robust and leads to better resolution of the pure components than classic MCR.  相似文献   
109.
A novel solid phase synthetic strategy was developed in this work for controlled functionalization of gold nanoparticles.  相似文献   
110.
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