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   301篇
  免费   12篇
  国内免费   3篇
电工技术   3篇
化学工业   79篇
金属工艺   7篇
机械仪表   4篇
建筑科学   3篇
能源动力   13篇
轻工业   13篇
无线电   41篇
一般工业技术   71篇
冶金工业   19篇
原子能技术   1篇
自动化技术   62篇
  2023年   2篇
  2022年   11篇
  2021年   16篇
  2020年   7篇
  2019年   6篇
  2018年   19篇
  2017年   7篇
  2016年   5篇
  2015年   8篇
  2014年   10篇
  2013年   24篇
  2012年   12篇
  2011年   7篇
  2010年   11篇
  2009年   9篇
  2008年   13篇
  2007年   16篇
  2006年   16篇
  2005年   11篇
  2004年   12篇
  2003年   7篇
  2002年   5篇
  2001年   8篇
  2000年   6篇
  1999年   3篇
  1998年   13篇
  1997年   4篇
  1996年   7篇
  1995年   5篇
  1994年   3篇
  1993年   2篇
  1992年   4篇
  1991年   6篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1985年   2篇
  1983年   2篇
  1981年   3篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1973年   2篇
  1972年   1篇
排序方式: 共有316条查询结果,搜索用时 31 毫秒
31.
Isolated aromatic interactions in designed octapeptide β‐hairpin scaffolds display a near‐universal T‐shaped face‐to‐edge geometry in all positional permutations, with the exception of aryl‐Trp interactions. The heterogeneous asymmetric indole ring of Trp competes for a “shielding” face geometry, which lowers the scaffold stability in FtE aryl‐Trp pairs. Assessment of the contributions of aryl pairs (in the absence of solvent‐driven interactions) to the overall β‐hairpin structure reveals the superiority of Trp‐Phe and Trp‐Tyr contributions over the well‐established scaffold stabilization by Trp‐Trp.  相似文献   
32.
By utilizing some of the important properties of wavelets like denoising, compression, multiresolution along with the concepts of fuzzy logic and neural network, two fuzzy wavelet neural networks (FWNNs) are proposed for approximating any arbitrary non‐linear function, hence, identifying a non‐linear system. We have fuzzified the output of DWT block, which receives the given inputs, in the proposed two methods: one using compression property and other using multiresolution property. We present a new type of fuzzy neuron model, each non‐linear synapse of which is characterized by a set of fuzzy implication rules with singleton weights in their consequents. It is shown that noise and disturbance in the reference signal are reduced with wavelets and also the variation of somatic gain, the parameter that controls the slope of the activation function in the neural network, leads to more accurate output. Identification results are found to be accurate and speed of their convergence is fast. Next, we simulate a control system for keeping output at a desired level by using the identified models. Two self‐learning controllers are designed in this simulation. One is a self‐learning fuzzy PI controller and other is a NN controller. Simulation results show that the NN controller is more adaptive and fast. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
33.
Therapeutic drug monitoring in the newborn infant is necessary because dose requirements differ greatly from those for older children. These differences stem from major changes in kinetic disposition at the absorption, distribution, and elimination phases. The small blood volume of neonates makes them sensitive to iatrogenic blood loss. Similarly, the small size of these patients means that medication errors frequently lead to morbidity and even mortality. The clinical laboratory must set up strict, high-standard, carefully updated guidelines to ensure the safety of infants who need drug therapy at this very vulnerable phase of their lives.  相似文献   
34.
Live recombinant Saccharomyces cerevisiae yeast expressing the envelope antigen of Japanese encephalitis virus (JEV) on the outer mannoprotein layer of the cell wall were examined for their ability to induce antigen‐specific antibody responses in mice. When used as a model antigen, parenteral immunization of mice with surface‐expressing GFP yeast induced a strong anti‐GFP antibody response in the absence of adjuvants. This antigen delivery approach was then used for a more stringent system, such as the envelope protein of JEV, which is a neurotropic virus requiring neutralizing antibodies for protection. Although 70% of cells were detected to express the total envelope protein on the surface by antibodies raised to the bacterially expressed protein, polyclonal anti‐JEV antibodies failed to react with them. In marked contrast, yeast expressing the envelope fragments 238–398, 373–399 and 373–500 in front of a Gly–Ser linker were detected by anti‐JEV antibodies as well as a monoclonal antibody but not by antibodies raised to the bacterially expressed protein. Immunization of mice with these surface‐expressing recombinants resulted in a strong antibody response. However, the antibodies failed to neutralize the virus, although the fragments were selected based on neutralizing determinants. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
35.
36.
A new alternate route for the production of SiC from rice husks has been described. The proposed single-stage process has the advantage of reduced time of production and a much higher yield of SiC whiskers than the conventional two-stage process. Direct pyrolysis of raw rice husks was carried out in a graphite furnace under vacuum and the reaction products were analyzed through macroscopic examination, XRD, SEM, and chemical analysis. Effects of time and temperature on the relative yields of the various reaction products have been determined over a wide range. The pyrolysis of raw rice husks has been found to be accompanied by four different competitive processes, viz., formation of SiC whiskers, formation of SiC polycrystals, crystallization of amorphous silica, and graphitization of amorphous carbon. Crystallization of silica and formation of SiC( w ) are dominant processes at 1150° to 1310°C. At higher temperatures formation of SiC polycrystals and graphitization of carbon are more favored. A multistep pyrolysis to 1310°C was found to yield a still higher amount of SiC( w ) than direct pyrolysis.  相似文献   
37.
We have solved the crystal structure of the Fab fragment of NMC-4, a mouse monoclonal antibody that binds to the A1 domain of von Willebrand factor (vWF). Two Asp and three Tyr residues in the complementarity determining regions 1 and 3 of the heavy chain exhibited a spatial orientation suggestive of a dominant role in establishing contact with the antigen. A cluster of Asp and Tyr residues occurs also in a region of the platelet glycoprotein (GP) Ib alpha amino terminal domain known to be critically involved in vWF binding. Thus, the structural information obtained with NMC-4 may prove relevant to understand the stereochemical bases of the GP Ib alpha-vWF interaction essential for thrombus formation at sites of vascular lesion.  相似文献   
38.
39.
3D weaving exhibits to be a guaranteeing innovation in delivering integrated near net shaped structures that might overcome the current issue of delamination and assembly cost. This paper highlights one such technique of producing preforms with integrally woven stiffener sections that can be used as a reinforcement material for composite panels. The woven performs were fabricated using high performance polyester yarns as a raw material and further consolidated to composite structures using epoxy resin. The flexural analysis of the composite panels developed from these performs revealed that the structures have better bending rigidity and structural integrity without any possibility of delamination prone failures. Investigations on fracture morphology were conducted to understand the composite failure mechanism and the structural deformation of the structures during loading. From the findings, it was evident that the polyester-epoxy material combination exhibited substantial residual strength and toughness properties.  相似文献   
40.
In the present study, we investigate the fundamental properties of CeO2 by selecting La3+ (57), and Dy3+ (66) as dopants with optimized average atomic number of 61.5, which lies in between Pm3+ (62) and Sm3+ (62) in accordance with the criteria for optimum doping. A system of co-doped ceria ceramics Ce1–x–yLaxDyyO2-δ ((x, y) = (0.00, 0.00), (0.025, 0.025), (0.05, 0.05), (0.075, 0.075), (0.10, 0.10), (0.00, 0.20) and (0.20, 0.00)) as electrolytes for intermediate temperature solid oxide fuel cells were successfully prepared by a well-known sol-gel auto-combustion route. In order to obtain dense samples, the prepared pellets were sintered in air at 1300 °C for 4 h using conventional furnace and relative densities of all the samples were found to be higher than 95%. Single phase cubic structure, microstructural density and elemental composition analysis of all the samples were studied by powder X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy techniques, respectively. Raman spectroscopy analysis confirmed the formation of concentrated O2-–vacancies in the co-doped ceria system. Impedance spectroscopy measurements revealed the high value of total ionic conductivity and low activation energy for the composition Ce0.85La0.075Dy0.075O2?δ i.e., 2.08 × 10–2 S cm–1 and 0.58 eV, respectively. Linear thermal expansion analyses of all the samples revealed the matched thermal expansion coefficients. Finally, these results recommend that the Ce0.85La0.075Dy0.075O2?δ sample can be useful as a solid electrolyte in IT-SOFC applications.  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