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   592篇
  免费   8篇
  国内免费   4篇
化学   191篇
晶体学   3篇
力学   10篇
数学   279篇
物理学   121篇
  2022年   7篇
  2021年   9篇
  2020年   2篇
  2019年   5篇
  2018年   10篇
  2017年   11篇
  2016年   22篇
  2015年   16篇
  2014年   23篇
  2013年   44篇
  2012年   41篇
  2011年   33篇
  2010年   29篇
  2009年   29篇
  2008年   43篇
  2007年   19篇
  2006年   32篇
  2005年   22篇
  2004年   17篇
  2003年   16篇
  2002年   28篇
  2001年   11篇
  2000年   11篇
  1999年   7篇
  1998年   15篇
  1997年   2篇
  1996年   14篇
  1995年   2篇
  1994年   3篇
  1993年   5篇
  1992年   2篇
  1991年   4篇
  1990年   5篇
  1989年   8篇
  1988年   4篇
  1986年   4篇
  1985年   4篇
  1984年   4篇
  1983年   4篇
  1982年   3篇
  1981年   3篇
  1980年   5篇
  1979年   3篇
  1978年   4篇
  1977年   2篇
  1976年   4篇
  1973年   3篇
  1970年   2篇
  1969年   2篇
  1936年   1篇
排序方式: 共有604条查询结果,搜索用时 15 毫秒
601.
New vapor-liquid equilibria (VLE) data at 333.15, 343.15, and 353.15 K and pressures up to 130.0 bar are reported for the carbon dioxide + 2-methyl-1-propanol (isobutanol) system. The experimental method used in this work was a static analytical method with liquid and vapor phases sampling using a rapid online sampler injector (ROLSITM) coupled to a gas chromatograph (GC) for analysis. Measured VLE data and literature data for carbon dioxide + 2-methyl-1-propanol system were modeled with the Soave-Redlich-Kwong (SRK) cubic equation of state with classical van der Waals (two-parameter conventional mixing rule, 2PCMR) mixing rules. A single set of interaction parameters that lead to a correct phase behavior was used in this work to model the new VLE data and critical points of the mixtures in a wide range of temperature and pressure. The SRK prediction results were compared to the new data measured in this study and to available literature data.
  相似文献   
602.
In this paper we show that the new approach to the embedding of the inflationary potentials into supergravity, presented in a quite recent paper [11] of Ferrara, Kallosh, Linde and Porrati can be formulated within the framework of standard matter coupled supergravity, without the use of the new minimal auxiliary set and of conformal compensators. The only condition is the existence of a translational Peccei Quinn isometry of the scalar Kähler manifold. We suggest that this embedding strategy based on a nilpotent gauging amounts to a profound Copernican Revolution. The properties of the inflaton potential are encoded in the geometry of some homogeneous one‐dimensional Kähler manifolds that now should be regarded as the primary object, possibly providing a link with microscopic physics. We present a simple and elegant formula for the curvature of the Kähler manifold in terms of the potential. Most relevant consequence of the new strategy is that all the integrable potentials quite recently classified in a paper [7] that we have coauthored, are automatically embedded into supergravity and their associated Kähler manifolds demand urgent study. In particular one integrable potential that provides the best fit to PLANCK data seems to have inspiring geometrical properties deserving further study.  相似文献   
603.
Summary : Cold plasma as source for charged particles was used to induce nanotopographies on homopolymeric surfaces (nylon 12, PMMA, PMA, etc.). Hydrogen and helium plasmas were successfully used for surface nanoengineering of polymers using inductively coupled or atmospheric pressure non-equilibrium barrier discharge reactors. AFM analyses reveal the presence of nanotopographies on the treated surfaces. Physical factors control the process below the Tg and chemical factors dominate the process above Tg. Pyrolysis GC/MS analyses have been performed in order to obtain more information about the plasma processes. Cold plasma chemical processes, including charges effects are discussed as tools that open-up new ways for nanoengineering of the polymers' surfaces with specific functionalities and / or topography. Future nanomanufacturing techniques can generate anti-scratch, superhydrophobic or superhydrophilic properties on surface of every day use polymeric products by simple and convenient plasma enhanced processes.  相似文献   
604.
The Work includes identifying and analyzing vibrations produced by a trilling machine MA750 within space work. To identify vibration is used a special method, which has not been used so far in identifying vibrations, with the action on the human body. For obtaining a very good identification of the human body vibrations has been used the Moiré projection method. General conditions were applied to human hand operator during working hours on a trilling machine, with different speeds of main shaft. In the paper are presented successively two methods of measuring the vibrations: the Moiré projection method and conventional method of measuring the vibrometer. The results in the booth situation (classical measurements and Moiré projection method) were in the same order of the unit scale, and the optical method named Moiré projection method can be considered a valid method for the human vibrations measurements without touch of the surface. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)  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