首页 | 官方网站   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   4497篇
  免费   80篇
  国内免费   3篇
工业技术   4580篇
  2021年   33篇
  2020年   28篇
  2019年   21篇
  2018年   50篇
  2017年   35篇
  2016年   24篇
  2015年   29篇
  2014年   52篇
  2013年   234篇
  2012年   90篇
  2011年   115篇
  2010年   84篇
  2009年   116篇
  2008年   132篇
  2007年   150篇
  2006年   128篇
  2005年   101篇
  2004年   105篇
  2003年   117篇
  2002年   81篇
  2001年   92篇
  2000年   76篇
  1999年   121篇
  1998年   466篇
  1997年   271篇
  1996年   188篇
  1995年   153篇
  1994年   127篇
  1993年   132篇
  1992年   70篇
  1991年   75篇
  1990年   62篇
  1989年   53篇
  1988年   62篇
  1987年   43篇
  1986年   44篇
  1985年   40篇
  1984年   34篇
  1983年   46篇
  1982年   48篇
  1981年   45篇
  1980年   45篇
  1979年   35篇
  1978年   29篇
  1977年   79篇
  1976年   91篇
  1975年   41篇
  1973年   23篇
  1972年   29篇
  1966年   19篇
排序方式: 共有4580条查询结果,搜索用时 15 毫秒
101.
102.
103.
The role of cobalt oxide in metal precipitation is explained on the basis of the influence of cobalt oxide on the reaction 4FeO ↔ Fe + Fe3O4. The temperature intervals during the firing cycle at which precipitation takes place and the relative rates of precipitation in ground coats of varying composition have been determined by a method of electrical conductivity at high temperatures.  相似文献   
104.
105.
The academic literature in 2000 presented a procedure for solving the job-shop-scheduling problem of minimizing L max. The iterative-adaptive simulation-based procedure is shown here to perform well on large-scale problems. However, there is potential for improvement in closing the gap between best-known solutions and the lower bound. In the present paper, a simulated annealing post-processing procedure is presented and evaluated on large-scale problems. A new neighbourhood structure for local searches in the job-shop scheduling problem is developed. The procedure is also evaluated using benchmark problems and new upper bounds are established.  相似文献   
106.
We derive a general reduced model for the flow of a slender thread of viscous fluid on a grooved substrate. Specific choices of the substrate topography allow further analytic progress to be made, and we subsequently focus on a convection–diffusion equation governing the evolution of viscous liquid in a wedge geometry. The model equation that arises also appears in the context of foam drainage, and we take the opportunity to review and compare the results from both applications. After summarising the constant mass results, we introduce a time-dependent fluid influx at one end of the wedge. The analytical results are supported by numerical computations.  相似文献   
107.
Abstract

We have studied the decoherence of motional-state superpositions of single trapped ions caused by their coupling to fluctuating fields. We illustrate these studies by showing how Schrödinger-cat state superpositions decohere in the presence of purposely-applied uniform stochastic electric fields and we compare these results to the decoherence caused by ambient fields in the experiments.  相似文献   
108.
Past research has found that tailoring increases the persuasive effectiveness of a message. However, the observed effect has been small and the explanatory mechanism remains unknown. To address these shortcomings, a tailoring software program was created that personalized breast cancer screening pamphlets according to risk, health belief model constructs, and visual preference. Women aged 40 and older (N = 119) participated in a 2 (Tailored vs. Stock Message) × 2 (Charts/Graphs vs. Illustrated Visuals) × 3 (Nested Replications of the Visuals) experiment. Participants provided with tailored illustrated pamphlets expressed greater breast cancer screening intentions than those provided with other pamphlets. In a test of 10 different mediators, perceived message relevance was found to fully mediate the Tailoring × Visual interaction.  相似文献   
109.
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-23

京公网安备 11010802026262号