全文获取类型
收费全文 | 353篇 |
免费 | 18篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 92篇 |
金属工艺 | 10篇 |
机械仪表 | 8篇 |
建筑科学 | 8篇 |
能源动力 | 11篇 |
轻工业 | 26篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 32篇 |
一般工业技术 | 84篇 |
冶金工业 | 13篇 |
自动化技术 | 78篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 19篇 |
2020年 | 13篇 |
2019年 | 9篇 |
2018年 | 15篇 |
2017年 | 22篇 |
2016年 | 20篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 20篇 |
2012年 | 16篇 |
2011年 | 23篇 |
2010年 | 20篇 |
2009年 | 16篇 |
2008年 | 16篇 |
2007年 | 19篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有373条查询结果,搜索用时 187 毫秒
21.
G. R. R. A. Kumara A. Konno G. K. R. Senadeera P. V. V. Jayaweera D. B. R. A. De Silva K. Tennakone 《Solar Energy Materials & Solar Cells》2001,69(2)
A method is devised for the deposition of CuSCN on ruthenium bipyridyl dye coated nanocrystalline TiO2 films from a solution in n-propyl sulphide. The dye-sensitized solid state photovoltaic cell formed was found to yield higher short-circuit photocurrent, open-circuit voltage and efficiency compared to the cells made with CuSCN by other deposition techniques. Factors affecting the stability of the cell are investigated. 相似文献
22.
Hongzhi Xie Yi‐Fen Li Hiromi K. Kagawa Jonathan D. Trent Kumara Mudalige Mircea Cotlet Basil I. Swanson 《Small (Weinheim an der Bergstrasse, Germany)》2009,5(9):1036-1042
Genetic engineering of a novel protein–nanoparticle hybrid system with great potential for biosensing applications and for patterning of various types of nanoparticles is described. The hybrid system is based on a genetically modified chaperonin protein from the hyperthermophilic archaeon Sulfolobus shibatae. This chaperonin is an 18‐subunit double ring, which self‐assembles in the presence of Mg ions and ATP. Described here is a mutant chaperonin (His‐β‐loopless, HBLL) with increased access to the central cavity and His‐tags on each subunit extending into the central cavity. This mutant binds water‐soluble semiconductor quantum dots, creating a protein‐encapsulated fluorescent nanoparticle. The new bioconjugate has high affinity, in the order of strong antibody–antigen interactions, a one‐to‐one protein–nanoparticle stoichiometry, and high stability. By adding selective binding sites to the solvent‐exposed regions of the chaperonin, this protein–nanoparticle bioconjugate becomes a sensor for specific targets. 相似文献
23.
Sagar V. Kamarthi Soundarr T. Kumara Francis T. S. Yu Inyong Ham 《Journal of Intelligent Manufacturing》1990,1(2):125-140
Neural networks have gained increased importance in the past few years. One of the basic characteristics of neural networks is the property of associative memory. In this paper we study the possibility of using the ideas of neural networks and associative memory in the manufacturing domain, with specific reference to design data retrieval in group technology. A two-layer feed-forward perceptron with backpropagation is simulated on a Vax-8550 to train example parts. The complete scheme along with the simulation results are explained and future directions indicated. 相似文献
24.
K.A.T. Amalka Perera S. Gaveshana Anuradha G.R. Asoka Kumara M. Lal Paranawitharana R.M. Gamini Rajapakse H.M.N. Bandara 《Electrochimica acta》2011,(11):19
Design, Development, fabrication and investigation of the I–V characteristics of the DSSC based on interconnected 15 nm SnO2 nanoparticles covered with a nano-scale thin layer of CaCO3 are described. The presence of CaCO3 has been confirmed by its characteristic XRD pattern and EDX plots. The thickness of the protective layer can be conveniently controlled by the molar ratio of SnO2:CaCO3 used in the preparation of the thin film and the optimum conditions for best performance of the DSSC are presented together with possible explanations for the variations observed when the molar ratio is changed. An optimum light-to-electricity conversion efficiency of 5.4% in the presence of a layer of CaCO3 has been obtained which is 3.2 times enhancement over the cell prepared without CaCO3. The characterization of the surface using different techniques is explained. 相似文献
25.
Aruna V. Murthy B. Dattaguru H. V. L. Narayana A. K. Rao 《Computers & Structures》1990,36(6):1121-1128
Accurate, reliable and economical methods of determining stress distributions are important for fastener joints. In the past the contact stress problems in these mechanically fastened joints using interference or push or clearance fit pins were solved using both inverse and iterative techniques. Inverse techniques were found to be most efficient, but at times inadequate in the presence of asymmetries. Iterative techniques based on the finite element method of analysis have wider applications, but they have the major drawbacks of being expensive and time-consuming. In this paper an improved finite element technique for iteration is presented to overcome these drawbacks. The improved iterative technique employs a frontal solver for elimination of variables not requiring iteration, by creation of a dummy element. This automatically results in a large reduction in computer time and in the size of the problem to be handled during iteration. Numerical results are compared with those available in the literature. The method is used to study an eccentrically located pin in a quasi-isotropic laminated plate under uniform tension. 相似文献
26.
D. B. Sirdeshmukh T. Kumara Swamy P. Geeta Krishna K. G. Subhadra 《Bulletin of Materials Science》2003,26(2):261-265
Efforts are made to improve the hardness of rubidium halide crystals by (i) solid solution hardening and (ii) impurity hardening.
Systematic microhardness measurements have been made on rubidium halide mixed crystals (RbBr-RbI and KI-RbI) and rubidium
halide crystals doped with Sr2+ ions. The composition dependence of the hardness of mixed crystals follows the law ΔH
v
=K x
(1− x),where ΔH
v
is the enhancement in hardness,K a constant andx and (1 −x) the concentrations of the first and second component of the mixed crystals, respectively. The hardness of doped crystals
increases with the concentrationC of the dopant according to the law, ΔH
v+6 =k C
m
,wherek andm are constants. The relative efficacy of the two methods of hardening is discussed. 相似文献
27.
Aruna Bahadur 《Journal of Materials Science》1987,22(6):1941-1944
The behaviour of a few Al-Mg alloys (up to 7.1 wt% Mg) has been studied on heating in air at 500°C for 8 h or more. The precipitation of a spinel phase, MgAl2O4, is found to take place on the surface and along the transverse section (depth) of the specimen. The alloys seem to be resistant to internal oxidation below 4.5% Mg and thereafter prone to it. Beryllium modification does not suppress the progress of internal oxidation taking place in the Al-Mg alloys. The results have been interpreted on the basis of anodized photomicrographs and X-ray diffraction data. 相似文献
28.
Kundu B Nandi SK Dasgupta S Datta S Mukherjee P Roy S Singh AK Mandal TK Das P Bhattacharya R Basu D 《Journal of materials science. Materials in medicine》2011,22(3):705-720
A systematic and extensive approach incorporating in vitro and in vivo experimentation to treat chronic osteomyelitis in animal model were made using antibiotic loaded special bioactive glass porous scaffolds. After thorough characterization for porosity, distribution, surface charge, a novel drug composite were infiltrated by using vacuum infiltration and freeze-drying method which was subsequently analyzed by SEM-EDAX and studied for in vitro drug elution in PBS and SBF. Osteomyelitis in rabbit was induced by inoculation of Staphylococcus aureus and optimum drug-scaffold were checked for its efficacy over control and parenteral treated animals in terms of histopathology, radiology, in vivo drug concentration in bone and serum and implant-bone interface by SEM. It was optimized that 60P samples with 60-65% porosity (bimodal distribution of macro- to micropore) with average pore size ~60 μm and higher interconnectivity, moderately high antibiotic adsorption efficiency (~49%) was ideal. Results after 42 days showed antibiotic released higher than MIC against S. aureus compared to parenteral treatment (2 injections a day for 6 weeks). In vivo drug pharmacokinetics and SEM on bone-defect interface proved superiority of CFS loaded porous bioactive glass implants over parenteral group based on infection eradication and new bone formation. 相似文献
29.
Single crystals of Lithium Ammonium Sulphate doped with Cu2+ ions were grown by slow evaporation technique. Electronic absorption spectra have been recorded at room and liquid nitrogen temperatures on Cary-2390 spectrophotometer. The spectrum is characteristic of a Cu2+ ion in octahedral symmetry. From the magnitude and and relative position of the bands a successful interpretation of all the observed bands has been made. The crystal field and tetragonal field parameters are derived. The observed and calculated energies are in good agreement. 相似文献
30.
Wang C. Cannon D.J. Kumara S.R.T. Guowen Lu 《Neural Networks, IEEE Transactions on》1995,6(5):1201-1211
This paper introduces an approach to cosmetic surface flaw identification that is essentially invariant to changes in workpiece orientation and position while being efficient in the use of computer memory. Visual binary images of workpieces are characterized according to the number of pixels in progressive subskeleton iterations. Those subskeletons are constructed using a modified Zhou skeleton transform with disk shaped structuring elements. Two coding schemes are proposed to record the pixel counts of succeeding subskeletons with and without lowpass filtering. The coded pixel counts are on-line fed to a supervised neural network that is previously trained by the backpropagation method using flawed and unflawed simulation patterns. The test workpiece is then identified as flawed or unflawed by comparing its coded pixel counts to associated training patterns. Such off-line trainings using simulated patterns avoid the problems of collecting flawed samples. Since both coding schemes tremendously reduce the representative skeleton image data, significant run time in each epoch is saved in the application of neural networks. Experimental results are reported using six different shapes of workpieces to corroborate the proposed approach. 相似文献