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   449495篇
  免费   6450篇
  国内免费   1228篇
化学   242836篇
晶体学   5424篇
力学   19051篇
综合类   13篇
数学   53167篇
物理学   136682篇
  2021年   3832篇
  2020年   4570篇
  2019年   4862篇
  2018年   6391篇
  2017年   6213篇
  2016年   9740篇
  2015年   6227篇
  2014年   9229篇
  2013年   21643篇
  2012年   17163篇
  2011年   20926篇
  2010年   14441篇
  2009年   14098篇
  2008年   19011篇
  2007年   18830篇
  2006年   17418篇
  2005年   15604篇
  2004年   14339篇
  2003年   12505篇
  2002年   12156篇
  2001年   13284篇
  2000年   9758篇
  1999年   7542篇
  1998年   6154篇
  1997年   6007篇
  1996年   5831篇
  1995年   5447篇
  1994年   5432篇
  1993年   5263篇
  1992年   5864篇
  1991年   5890篇
  1990年   5643篇
  1989年   5437篇
  1988年   5452篇
  1987年   5361篇
  1986年   5042篇
  1985年   6598篇
  1984年   6701篇
  1983年   5307篇
  1982年   5384篇
  1981年   5366篇
  1980年   4928篇
  1979年   5364篇
  1978年   5491篇
  1977年   5397篇
  1976年   5347篇
  1975年   4925篇
  1974年   4883篇
  1973年   4907篇
  1972年   3464篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Mathematical Notes - A system of new differential-geometric notions as the result of an analysis of the Trudinger–Wang inequalities is proposed. Their naturalness in multivariate analysis and...  相似文献   
23.
Journal of Applied Mechanics and Technical Physics - A self-equilibrated stress field for an incompressible sphere is constructed based on a non-Euclidean continuum model. The...  相似文献   
24.
International Journal of Theoretical Physics - The interaction between two modes quantized field and asymmetric two atoms represents one of the important quantum models to study the nonclassical...  相似文献   
25.

Organisations are concerned about measuring the performance of the product/service they deliver to their customers. In all types of organisations, if a proper performance assessment is to be developed, it should be measured in different dimensions. At University, the new study programs include the development and assessment of transversal competences due to their importance in enhancing the abilities and improving the employability of students. The achievement of transversal competences can be assessed in different levels/stages; for example, the 1st and 2nd years of a Bachelor’s degree; the 3rd and 4th years of a Bachelor’s degree and at Master’s level. The purpose of this paper is to integrate the research into performance management in organisations to develop an approach consisting of four components (a methodology, a solid and integrated performance management framework, graphical diagrams and quantitative techniques) to assess and manage the achievement of transversal competences through the different levels of study using a consolidated approach. The proposal uses the Analytic Network Process (ANP) to model dependences and feedback among the elements of the competences.

  相似文献   
26.
JETP Letters - The results of the first run (December 2020) for the commissioning of the new superconducting synchrotron Booster at the Joint Institute for Nuclear Research are presented. Vacuum...  相似文献   
27.
Journal of Applied Spectroscopy - Multivariate models were developed on the basis of raw low-resolution LIBS spectra of reference samples of lowalloy steels for calibration of the concentrations of...  相似文献   
28.
Shabara  R. M.  Alsobhi  B. O. 《JETP Letters》2021,113(5):322-330
JETP Letters - The electronic, elastic, and magnetic properties of the new full Heusler alloys Ru2XY with X = Nb, Mn and Y = Te, Sb are investigated using the Full Potential Nonorthogonal...  相似文献   
29.
Technical Physics - A high-voltage system for electron cooling of the COSY (Germany) synchrotron is featured by the presence of a profile monitor that is used for measurement of current density...  相似文献   
30.

A model with 16 moments is here presented in the framework of RET of polyatomic gases. It furnishes as principal subsystem the relativistic counterpart of a work by Arima T., Ruggeri T., Sugiyama M.; this is present in literature and treats the non relativistic case which incorporates relaxation processes of molecular rotation and vibration. Another principal subsystem is the natural extension of the 14 moments model by Pennisi S. and Ruggeri T.; this is also present in literature in the relativistic framework but where the trace of the third balance equation is neglected. Its extension is found here for the case when this trace isn’t neglected.

  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