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   4303篇
  免费   410篇
  国内免费   5篇
电工技术   47篇
综合类   1篇
化学工业   1363篇
金属工艺   155篇
机械仪表   110篇
建筑科学   141篇
矿业工程   24篇
能源动力   173篇
轻工业   861篇
水利工程   20篇
石油天然气   11篇
无线电   196篇
一般工业技术   807篇
冶金工业   168篇
原子能技术   9篇
自动化技术   632篇
  2023年   39篇
  2022年   127篇
  2021年   338篇
  2020年   164篇
  2019年   176篇
  2018年   255篇
  2017年   242篇
  2016年   280篇
  2015年   226篇
  2014年   296篇
  2013年   477篇
  2012年   284篇
  2011年   227篇
  2010年   184篇
  2009年   223篇
  2008年   173篇
  2007年   146篇
  2006年   107篇
  2005年   69篇
  2004年   65篇
  2003年   66篇
  2002年   49篇
  2001年   24篇
  2000年   34篇
  1999年   21篇
  1998年   21篇
  1997年   15篇
  1996年   16篇
  1995年   17篇
  1994年   16篇
  1993年   17篇
  1992年   13篇
  1991年   10篇
  1990年   19篇
  1988年   9篇
  1987年   12篇
  1986年   9篇
  1985年   20篇
  1984年   30篇
  1983年   36篇
  1982年   20篇
  1981年   25篇
  1980年   25篇
  1979年   19篇
  1978年   10篇
  1977年   10篇
  1976年   9篇
  1975年   9篇
  1974年   8篇
  1973年   9篇
排序方式: 共有4718条查询结果,搜索用时 171 毫秒
81.
In this paper it has been shown that, with the advent of lasers with a very short pulse duration, the effect of thermal wave propagation becomes important. To consider this effect, hyperbolic heat conduction in thin gold films was studied. It was shown that for heat fluxes of the order 108 W·cm–2, a thermal wave is generated in thin gold films. The consideration of the hyperbolicity of heat transfer enables one to describe the temperature profile with one value of fluence.  相似文献   
82.
83.
84.
Versatile optimization of the synthesis method and composition of Yb3+ and Tm3+ co-doped CaF2 nanoparticles as well as a novel biofunctionalization method were developed and evaluated.Through multistep synthesis,the luminescence intensity of the Tm3+ activator was enhanced by more than 10-fold compared to standard one-step synthesis.The proposed methods were used to homogenously distribute the doping ions within the nanoparticle's volume and thus reduce luminescence quenching.Optimization of dopant ions concentration led to the selection of the most efficient visible and near-infrared up-converting nanoparticles,which were CaF2 doped with 10% Yb3+ 0.05% Tm3+ and 20% Yb3+ 0.5% Tm3+,respectively.To illustrate the suitability of the synthesized nanoparticles as bio-labels,a dedicated biofunctionalization method was used,and the nanoparticles were applied for labeling and imaging of Candida albicans cells.This method shows great promise because of extremely low background and high specificity because of the presence of the attached molecules.  相似文献   
85.
Context: Continuous processing is an innovative production concept well known and successfully used in other industries for many years. The modern pharmaceutical industry is facing the challenge of transition from a traditional manufacturing approach based on batch-wise production to a continuous manufacturing model.

Objective: The aim of this article is to present technological progress in manufacturing based on continuous and semi-continuous processing of the solid oral dosage forms.

Methods: Single unit processes possessing an alternative processing pathway to batch-wise technology or, with some modification, an altered approach that may run continuously, and are thus able to seamlessly switch to continuous manufacturing are briefly presented. Furthermore, the concept of semi-continuous processing is discussed. Subsequently, more sophisticated production systems created by coupling single unit processes and comprising all the steps of production, from powder to final dosage form, were reviewed. Finally, attempts of end-to-end production approach, meaning the linking of continuous synthesis of API from intermediates with the production of final dosage form, are described.

Results: There are a growing number of scientific articles showing an increasing interest in changing the approach to the production of pharmaceuticals in recent years. Numerous scientific publications are a source of information on the progress of knowledge and achievements of continuous processing. These works often deal with issues of how to modify or replace the unit processes in order to enable seamlessly switching them into continuous processing. A growing number of research papers concentrate on integrated continuous manufacturing lines in which the production concept of “from powder to tablet” is realized. Four main domains are under investigation: influence of process parameters on intermediates or final dosage forms properties, implementation of process analytical tools, control-managing system responsible for keeping continuous materials flow through the whole manufacturing process and the development of new computational methods to assess or simulate these new manufacturing techniques. The attempt to connect the primary and secondary production steps proves that development of continuously operating lines is possible.

Conclusion: A mind-set change is needed to be able to face, and fully assess, the advantages and disadvantages of switching from batch to continuous mode production.  相似文献   

86.
87.
The specific heat C(T) of the monoclinic RbDy(WO 4 ) 2 crystal has been studied at very low temperatures 0.2T1.9 K and in magnetic fields 0H0.38 T. The Neel temperature was shown to be equal to TN = 0.818 ± 0.005 K. The experimental value of the effective exchange parameter was obtained to be equal to J/k = – 0.798 K. The C T) dependence below Neel temperature 0.5TN0.99TN ) is well described by 2D Ising model, whereas in the temperature region close above TN (1.01 TN2TN) it can be described by neither 2D, nor 3D Ising model. The experimental and theoretical H-TN diagrams for field H a are in a reasonable agreement for simple quadratic lattice.  相似文献   
88.
89.
A method for bone strain estimation is examined in this article. The flexibility of a single bone in an otherwise rigid human skeleton model has been studied previously by various authors. However, in the previous studies, the effect of the flexibility of multiple bones on the musculoskeletal model behavior was ignored. This study describes a simulation method that can be used to estimate the bone strains at both tibias and femurs of a 65-year-old Caucasian male subject. The verification of the method is performed by the comparison of the results with other studies available in literature. The results of the study show good correlation with the results of previous empirical studies. A damping effect of the flexible bones on the model is also studied in this paper.  相似文献   
90.
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