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   1903篇
  免费   97篇
  国内免费   5篇
工业技术   2005篇
  2023年   10篇
  2022年   8篇
  2021年   27篇
  2020年   33篇
  2019年   39篇
  2018年   60篇
  2017年   43篇
  2016年   49篇
  2015年   45篇
  2014年   69篇
  2013年   113篇
  2012年   118篇
  2011年   132篇
  2010年   112篇
  2009年   117篇
  2008年   107篇
  2007年   88篇
  2006年   86篇
  2005年   59篇
  2004年   63篇
  2003年   45篇
  2002年   48篇
  2001年   37篇
  2000年   28篇
  1999年   44篇
  1998年   92篇
  1997年   72篇
  1996年   51篇
  1995年   46篇
  1994年   26篇
  1993年   26篇
  1992年   11篇
  1991年   12篇
  1990年   5篇
  1989年   14篇
  1988年   8篇
  1987年   9篇
  1986年   8篇
  1985年   8篇
  1984年   5篇
  1983年   4篇
  1982年   5篇
  1981年   4篇
  1980年   7篇
  1979年   1篇
  1978年   2篇
  1976年   7篇
  1973年   1篇
  1971年   1篇
排序方式: 共有2005条查询结果,搜索用时 15 毫秒
81.
Using the method of recording anode potentiodynamic curves in neutral and mildly alkaline borate buffer solutions, the corrosion and electrochemical behavior of iron-armco samples bombarded with oxygen ions is studied. It is shown by the method of X-ray photoelectron spectroscopy that, during such bombardment, implantation of oxygen into the surface layers of iron occurs. Therein, iron oxides of variable composition and various forms of adsorbed and absorbed oxygen are formed. These oxygen formations contribute to transfer of the iron surface to a more corrosion-resistant, passive state.  相似文献   
82.
In this paper, different organic–inorganic hybrid materials based in the CaO–SiO2–poly(dimethyl siloxane) PDMS system have been characterised by means of nanoindentation and their static mechanical properties (Young’s modulus, and hardness) have been investigated. These mechanical properties have been discussed in relation to the chemical composition and structure of the different hybrid materials. Besides, the mechanical behaviour of hybrid materials is visco-elastic and it therefore presents phenomena of creep that will be influenced by the temperature of the mechanical test; undoubtedly, a temperature of 37°C accelerates the processes of creep.  相似文献   
83.
84.
85.
86.
Due to the increase in the number and popularity of applications such as e-commerce or on-line booking systems, typical of the Web 2.0, dynamic contents are becoming more and more frequent. This trend suggests the review of widely accepted paradigms and models for the World Wide Web. As a system that is continuously changing, both in the offered applications and in its infrastructure, performance evaluation studies are a main concern to provide sound proposals when designing new web-related systems. Although the dynamism in the workload characterization has also been tackled in previous research, it has not been modeled in a precise way yet because of its complex nature.In this paper we propose the Dweb model which represents the dynamism of current web applications in the workload characterization. Dweb is based on three main concepts that allow to model dynamic workload: navigation, workload test and workload distribution. In addition, a dynamic workload generator has been implemented to show the practical application of the proposed model, which has been illustrated through a case study.  相似文献   
87.
88.
89.
90.
Two red wines with a very high ethanol content were partially dealcoholized by reverse osmosis, so that the influence of this technique on wine color, chemical composition and sensory quality could be studied. No statistically significant differences were found in pH, color intensity, total phenolic index, proanthocyanidin concentration and their mean degree of polymerization between control wines and partially dealcoholized wines (?1 and ?2 vol. %). Some slight but significant differences were found in titratable acidity, anthocyanins, CIELab coordinates and polysaccharides. However, these differences were really quite small and only significant in a few cases. Moreover, a trained panel of tasters had severe difficulty in distinguishing between control and partially dealcoholized wines in triangular tests, and results were statistically significant only in some of the comparisons. It is concluded that this technique can be very useful for the partial dealcoholization of red wines because they hardly alter their composition and sensory characteristics.  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-23

京公网安备 11010802026262号