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   682篇
  免费   14篇
  国内免费   2篇
电工技术   1篇
化学工业   32篇
金属工艺   1篇
机械仪表   19篇
建筑科学   31篇
能源动力   32篇
轻工业   38篇
水利工程   5篇
无线电   49篇
一般工业技术   107篇
冶金工业   277篇
原子能技术   7篇
自动化技术   99篇
  2021年   9篇
  2020年   5篇
  2019年   2篇
  2018年   5篇
  2017年   5篇
  2016年   3篇
  2015年   9篇
  2014年   7篇
  2013年   35篇
  2012年   21篇
  2011年   22篇
  2010年   25篇
  2009年   23篇
  2008年   26篇
  2007年   26篇
  2006年   22篇
  2005年   19篇
  2004年   23篇
  2003年   11篇
  2002年   12篇
  2001年   13篇
  2000年   9篇
  1999年   19篇
  1998年   53篇
  1997年   43篇
  1996年   22篇
  1995年   18篇
  1994年   18篇
  1993年   25篇
  1992年   14篇
  1991年   7篇
  1990年   9篇
  1989年   5篇
  1988年   9篇
  1987年   10篇
  1986年   13篇
  1985年   11篇
  1984年   3篇
  1983年   11篇
  1982年   8篇
  1981年   7篇
  1980年   16篇
  1979年   2篇
  1978年   2篇
  1977年   6篇
  1976年   12篇
  1975年   9篇
  1974年   5篇
  1972年   2篇
  1967年   2篇
排序方式: 共有698条查询结果,搜索用时 352 毫秒
101.
Tested 9 deaf and 9 normal 15-27 yr olds on their ability to report letters, shapes, and nonsense figures from a tachistoscopic presentation. Deaf Ss performed worse than hearing Ss on recall of figural information, thereby supporting a linguistic coding hypothesis. However, there was no difference between the groups on position information, and letter confusions were primarily visual in both groups. Findings suggest that more attention should be given to visual short-term memory in theoretical models of memory. Formation of the icon was apparently not affected by a linguistic deficit, since effects of stimulus duration and type of viewing (continuous vs interrupted) were similar in both hearing and deaf Ss. Significant positive correlations which were found between deaf Ss' school reading scores and their tachistoscopic scores were not interpreted as support for a linguistic coding hypothesis, but rather as support for the notion that the memory skills tested in the experiment may underlie reading ability. (French summary) (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
102.
Global and element residuals are introduced to determine a posteriori, computable, error bounds for finite element computations on a given mesh. The element residuals provide a criterion for determining where a finite element mesh requires refinement. This indicator is implemented in an algorithm in a finite element research program. There it is utilized to automatically refine the mesh for sample two-point problems exhibiting boundary layer and interior layer solutions. Results for both linear and nonlinear problems are presented. An important aspect of this investigation concerns the use of adaptive refinement in conjunction with iterative methods for system solution. As the mesh is being enriched through the refinement process, the solution on a given mesh provides an accurate starting iterate for the next mesh, and so on. A wide range of iterative methods are examined in a feasibility study and strategies for interweaving refinement and iteration are compared.  相似文献   
103.
DNA aptamer-based bioanalysis of IgE by fluorescence anisotropy   总被引:3,自引:0,他引:3  
A rapid, homogeneous aptamer-based bioanalysis is reported for the sensitive detection of immunoglobulin E (IgE) using fluorescence polarization (FP). 5'-End-labeled D17.4 DNA aptamer was used for IgE detection based on the anisotropy differences of the labeled ligand. Two different fluorophores, fluorescein and Texas Red, were used to analyze IgE in the low-nanomolar range with high specificity. Measurable anisotropy changes were observed with a short equilibration time. Analysis of the binding data reveals a possible cooperative binding process in solution. The nature of the fluorophore clearly influences the sensitivity of the analysis more than the tether length used for the dye conjugation. The local fluorophore motion is seen to influence the sensitivity of the FP probe significantly. Texas Red is seen to be relatively more sensitive for this approach and has apparently favorable dye-DNA interactions, and a limit of detection of 350 pM was obtained. Significant temperature dependence of the FP responses has been observed in this work. Ionic composition of the binding buffer also influences the assay sensitivity. The results confirm the promise and potential of similar homogeneous assays for aptamer-based bioanalysis.  相似文献   
104.
Design requirements for an 8000 frame/s dual-wavelength ratiometric chemical species tomography system, intended for hydrocarbon vapor imaging in one cylinder of a standard automobile engine, are examined. The design process is guided by spectroscopic measurements on iso-octane and by comprehensive results from laboratory phantoms and research engines, including results on temporal resolution performance. Novel image reconstruction techniques, necessary for this application, are presented. Recent progress toward implementation, including details of the optical access arrangement employed and signal-to-noise issues, is described. We present first cross-cylinder IR absorption measurements from a reduced channel-count (nontomographic) system and discuss the prospects for imaging.  相似文献   
105.
Ergonomics is a key issue in the construction industry. Many work tasks and associated equipment and tools are not designed with ergonomics principles in mind. Often, in the development of power tools for construction, any attention to ergonomics is restricted to the human-machine interface and handle design. The need for ergonomics intervention in the development process originates from considerations of safety, health, physical work load, and productivity. It is argued that in each of these respects, the construction industry has lower standards than other industries and therefore has a need and opportunity for improvement. A multi-level ergonomics approach is proposed addressing these issues. The approach defines five levels of ergonomics intervention, from designing individual tools for safety, to designing wider aspects of construction and work flow for optimal productivity. This holistic approach is illustrated using case study examples of the development of power tools and work methods.  相似文献   
106.
107.
Suggests that the government should sustain science, give it a voice in the councils of public policy, and link its versatility to the ends of a purposeful society. This function has 5 implications for public policy, planning, resource allocation, and administration in science. (0 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
108.
A simple analytical model is used to examine the mechanical interaction of LMFBR core components with the surrounding coolant. Approximating a subassembly duct by a single degree of freedom oscillator and the coolant by a thin layer of viscous fluid, the problem was reduced to a nonlinear differential equation governing the motion of the oscillator. Approximate analytical and numerical solutions are presented which enable parametric studies useful in LMFBR core design.  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