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   3088篇
  免费   76篇
  国内免费   11篇
化学   2022篇
晶体学   8篇
力学   98篇
数学   459篇
物理学   588篇
  2023年   18篇
  2022年   64篇
  2021年   105篇
  2020年   63篇
  2019年   48篇
  2018年   44篇
  2017年   31篇
  2016年   79篇
  2015年   68篇
  2014年   75篇
  2013年   163篇
  2012年   157篇
  2011年   197篇
  2010年   111篇
  2009年   81篇
  2008年   199篇
  2007年   209篇
  2006年   163篇
  2005年   172篇
  2004年   125篇
  2003年   108篇
  2002年   95篇
  2001年   64篇
  2000年   40篇
  1999年   42篇
  1998年   34篇
  1997年   40篇
  1996年   34篇
  1995年   35篇
  1994年   43篇
  1993年   33篇
  1992年   37篇
  1991年   26篇
  1990年   17篇
  1989年   12篇
  1988年   16篇
  1987年   14篇
  1986年   15篇
  1985年   30篇
  1984年   23篇
  1983年   18篇
  1982年   25篇
  1981年   28篇
  1980年   19篇
  1979年   18篇
  1978年   15篇
  1977年   13篇
  1976年   14篇
  1975年   14篇
  1973年   12篇
排序方式: 共有3175条查询结果,搜索用时 34 毫秒
1.
Sun  Yekai  Yuan  Jie  Vizzaccaro  Alessandra  Salles  Loïc 《Nonlinear dynamics》2021,104(4):3077-3107
Nonlinear Dynamics - The nonlinear modes of a non-conservative nonlinear system are sometimes referred to as damped nonlinear normal modes (dNNMs). Because of the non-conservative...  相似文献   
2.
3.
4.
In this study, the functional interaction of HPLW peptide with VEGFR2 (Vascular Endothelial Growth Factor Receptor 2) was determined by using fast 15N‐edited NMR spectroscopic experiments. To this aim, 15N uniformly labelled HPLW has been added to Porcine Aortic Endothelial Cells. The acquisition of isotope‐edited NMR spectroscopic experiments, including 15N relaxation measurements, allowed a precise characterization of the in‐cell HPLW epitope recognized by VEGFR2.  相似文献   
5.
We report a strong dependence of the thermal stability of Nafion® perfluorosulfonate ionomer on the nature of the counterion associated with the fixed sulfonate site. These results were obtained using thermal gravimetric analysis on a series of alkali metal and alkyl ammonium cation-exchanged Nafion films. We have found that the temperature of decomposition of Nafion is inversely dependent on the size of the exchanged cation; i.e., Nafion films show improved thermal stability as the size of the counter cation decreases. We attribute this inverse relationship of thermal stability with counterion size to an initial decomposition reaction which is strongly influenced by the strength of the sulfonate-coun-terion interaction. © 1993 John Wiley & Sons, Inc.  相似文献   
6.
We introduce symmetric Boundary Value Methods for the solution of second order initial and boundary value problems (in particular Hamiltonian problems). We study the conditioning of the methods and link it to the boundary loci of the roots of the associated characteristic polynomial. Some numerical tests are provided to assess their reliability. Dedicated to the memory of Professor Aldo Cossu  相似文献   
7.
Summary We study the integration theory for general integral metrics when restricted to upper integrals q, finding improvements in the relation between the classes of the q-integrable and the ql-integrable functions. We give new results and notions which lead to the desirable characterizations of q-integrable functions as ql-integrable f with q(|f|) < ∞, and of ql-integrable functions via the integrability of their upper truncations, under natural conditions which are fulfilled in most finitely additive integration theories.  相似文献   
8.
This is the report of the subgroup QCD of Working Group-4 at WHEPP-9. We present the activities that had taken place in the subgroup and report some of the partial results arrived at following the discussion at the working group meetings.  相似文献   
9.
A comprehensive numerical tool has been developed for the evaluation of the performances of Radio over Fiber (RoF) links intended for wireless signal distribution.At the transmitter end an appropriate set of rate equations allows to model the optical source as a solitary laser or as an appropriately injection locked laser. The optical channel is modeled putting into account the combined effect of fiber dispersion, laser source non ideal performances (e.g. non-linear effects, frequency chirp), and quadratic detection of the receiving photodiode. The simulation model developed can be a useful tool at the design stage allowing a preliminary evaluation of the characteristics of real RoF links.  相似文献   
10.
Flow injection methodology based on sample insertion between two different standard solutions used as carrier streams is described. This approach provides a simple system for continuous recalibration in process control; spectrophotometric and ion-selective electrode procedures are outlined.  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