全文获取类型
收费全文 | 1291篇 |
免费 | 26篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 68篇 |
综合类 | 4篇 |
化学工业 | 292篇 |
金属工艺 | 30篇 |
机械仪表 | 34篇 |
建筑科学 | 15篇 |
能源动力 | 39篇 |
轻工业 | 92篇 |
水利工程 | 5篇 |
无线电 | 127篇 |
一般工业技术 | 218篇 |
冶金工业 | 288篇 |
原子能技术 | 20篇 |
自动化技术 | 87篇 |
出版年
2023年 | 10篇 |
2022年 | 20篇 |
2021年 | 22篇 |
2020年 | 11篇 |
2019年 | 21篇 |
2018年 | 22篇 |
2017年 | 19篇 |
2016年 | 23篇 |
2015年 | 16篇 |
2014年 | 25篇 |
2013年 | 65篇 |
2012年 | 51篇 |
2011年 | 72篇 |
2010年 | 30篇 |
2009年 | 47篇 |
2008年 | 53篇 |
2007年 | 43篇 |
2006年 | 38篇 |
2005年 | 42篇 |
2004年 | 32篇 |
2003年 | 42篇 |
2002年 | 34篇 |
2001年 | 18篇 |
2000年 | 25篇 |
1999年 | 23篇 |
1998年 | 116篇 |
1997年 | 66篇 |
1996年 | 57篇 |
1995年 | 26篇 |
1994年 | 24篇 |
1993年 | 35篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 17篇 |
1984年 | 8篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1976年 | 17篇 |
1975年 | 7篇 |
1974年 | 2篇 |
1973年 | 4篇 |
排序方式: 共有1319条查询结果,搜索用时 15 毫秒
21.
K HondaM Yoshimura R UchikadoT Kondo Tata N Rao D.A TrykA Fujishima M WatanabeK Yasui H Masuda 《Electrochimica acta》2002,47(27):4373-4385
Electrochemical characteristics for several redox systems at diamond films with highly ordered nanometer-scale cylindrical pores (‘nano-honeycombs’) were examined with cyclic voltammetry (CV) and electrochemical impedance measurements. The cyclic voltammetric anodic-cathodic peak separations for these nano-honeycomb electrodes were in the same range as those for polished polycrystalline diamond films, indicating that the involvement of the oxygen-terminated surface of the nano-pore walls, which should give rise to large peak separations for certain redox couples was only slight. Moreover, the peak currents in the CV were not enhanced to the extent expected on the basis of the roughness factors of the nano-honeycomb films. Ac impedance plots results indicated the existence of a concentration gradient of the reactant in the nano-pores, which is in agreement with theoretical predictions for charge transfer reactions in porous electrodes. The average concentration of the reactant (Fe2+/3+) inside the nano-pores was a factor of ca. 80 lower than that in the bulk electrolyte. The results of the impedance analysis also indicated an increase in the reaction resistances with decreasing pore diameters. 相似文献
22.
Extraction and implementation of muscle synergies in neuro-mechanical control of upper limb movement
Hang Pham Yohei Ariga Kenta Tominaga Takanori Oku Kanna Nakayama Mitsunori Uemura 《Advanced Robotics》2014,28(11):745-757
This work faces the redundancy problem, a central concern in robotics, in a particular force-producing task by using muscle synergies to simplify the control. We extracted muscle synergies from human electromyograph signals and interpreted the physical meaning of the identified muscle synergies. Based on the human analysis results, we hypothesized a novel control framework that can explain the mechanism of the human motor control. The framework was tested in controlling a pneumatic-driven robotic arm to perform a reaching task. This control method, which uses only two synergies as manipulated variables for driving antagonistic pneumatic artificial muscles to generate desired movements, would be useful to deal with the redundancy problem; thus, suggesting a simple but efficient control for human-like robots to work safely and compliantly with humans. 相似文献
23.
24.
Hitoshi Masuda Chiyoshi Kamizawa Kunio Hata Kingo Yokota Tomoo Sakai Mitsuhiro Sato 《Desalination》1978,25(1):89-97
The evaporation drain of sulfite pulp spent liquor contains few volatile fatty acids, most of which is acetic acid. The main objective of this study is to recover acetic acid as the concentrated solution (about 4%), which could be used as a culture medium of the yeast. As acetic acid can easily pass through the cellulose acetate membrane, SP drains neutralized by NaOH, NH4OH and Ca(OH)2 were used as the feed solutions. In all cases, concentration by reverse osmosis was successfully carried out provided the appropriate pretreatment was employed. The recovery of acetic acid was 95.6, 90.5 and 98.2% for Na-, NH4-, and Ca-drain, respectively. In addition, the recovered (permeated) water may be used as an industrial one. 相似文献
25.
In the copolymerization of phenylacetylene with various acetylenes catalysed by WCl6·Ph4Sn, the relative reactivity of monomer decreased with increasing steric effect of monomer, e.g. HC Cn-Bu, HC Cn-Hex > HC CPh, HC Cs-Bu > HC Ct-Bu, MeCCPh, CICCPh. While 1-chloro-2-phenylacetylene (a disubstituted acetylene) showed high reactivity in the homopolymerization by Mobased catalysts, the reactivity was remarkably depressed in the presence of phenylacetylene as comonomer. Based on these results, the relative reactivity of the acetylenic monomers in copolymerization was explained in terms of competitive coordination of monomers to the propagating end. 相似文献
26.
Effect of Fe-Zn alloy layer on the corrosion resistance of galvanized steel in chloride containing environments 总被引:2,自引:0,他引:2
In this study, the effect of Fe-Zn alloy layer that is formed during galvanizing process on the corrosion behavior of galvanized steel has been investigated. The galvanostatic dissolution of galvanized steel was carried out in 0.5 M NaCl solution to obtain the Fe-Zn alloy layer on the base steel. The alloy layer was characterized to be composed of FeZn13, FeZn7 and Fe3Zn10 intermetallic phases, which constitute the zeta, delta1 and gamma layers of galvanized steel, respectively. It was observed that the alloy layer has similar cathodic polarization behavior but different anodic polarization behavior compared to galvanized steel. The anodic current plateau of alloy layer was up to 100 times lower than that of galvanized coating. Corrosion test performed in wet-dry cyclic condition has shown that the alloy layer has lower corrosion rate as compared to galvanized steel. From the results of corrosion test of alloy layer and base steel, it was concluded that Zn2+ has positive effect on the protectiveness of the zinc corrosion products. The measurement of surface potential over the alloy/steel galvanic couple has confirmed the galvanic ability of alloy layer to protect both the alloy layer itself and the base iron during initial stage of atmospheric corrosion. 相似文献
27.
Takeshi Masuda 《Computer Vision and Image Understanding》2009,113(11):1158-1169
We propose a method for coarse registration of multiple range images that uses a log-polar height map (LPHM) as the key for establishing correspondence. The LPHM is a local height map orthogonally mapped on the tangent plane with the log-polar coordinate system. The input range images are roughly represented by signed distance field (SDF) samples. For each SDF sample, an LPHM is generated and is converted to an invariant feature vector. Point correspondence is established by a nearest neighbor search in feature space. The RANSAC algorithm is applied on the corresponding point pairs between each pair of range images, and the pairwise registration of input range images is determined by the extracted inlier point pairs. Finally, the global registration is determined by constructing a view tree, which is the spanning tree that maximizes the total number of inlier point pairs. The result of coarse registration is used as the initial state of the fine registration and modeling. The proposed method was tested on multiple real range image datasets. 相似文献
28.
Summary 3-(N-Carbazolyl)-1-propyne polymerized with MoCl5- and WCl6-based catalysts to produce a polymer in high yields. The MoCl5 and MoCl5-n-Bu4Sn catalysts were the most effective (the systems solidified immediately after initiation of polymerization with these catalysts). The product polymer was a yellow solid insoluble in any solvent. Copolymerization of the present monomer with tert-butylacetylene by MoCl5-n-Bu4Sn produced a copolymer; it had a high molecular weight (M
w 350,000), completely dissolved in toluene, CHCl3 etc, and formed a free-standing film by solution casting. -N-Carbazolyl-1-hexyne and-1-octyne produced toluene-insoluble polymers with WCl6-Ph4Sn. 相似文献
29.
The method for measurement of ruthenium isotopic composition as RuO(3)(-) by negative thermal ionization mass spectrometry (NTI-MS) is shown to be sensitive and accurate. Precise measurement of the (18)O/(16)O ratio, which is important for oxygen correction in NTI-MS, has also been made. Both Re and Pt filaments were tested, and the latter was proved to be more efficient for negative ion production. The mechanism of ion production with the addition of HI as a reducing reagent and Ba(NO(3))(2) as an ionizing enhancer was also studied. Sensitivity was found to be about 100 times higher than that of the positive mode. Factors related to negative ion formation are discussed, and parameters are optimized. The ionization efficiency has been improved to 0.7%. Ten nanograms of Ru yielded a total ion current of 3 × 10(-12) A for 1 h. The precisions of all Ru isotope ratios with a 100 ng sample size were better than 0.009%. 相似文献
30.
CW Ponton M Don JJ Eggermont MD Waring B Kwong A Masuda 《Canadian Metallurgical Quarterly》1996,8(1):61-65
Separation and identification of proteins by two-dimensional (2-D) electrophoresis can be used for protein-based gene expression analysis. In this report single protein spots, from polyvinylidene difluoride blots of micropreparative E. coli 2-D gels, were rapidly and economically identified by matching their amino acid composition, estimated pI and molecular weight against all E. coli entries in the SWISS-PROT database. Thirty proteins from an E. coli 2-D map were analyzed and identities assigned. Three of the proteins were unknown. By protein sequencing analysis, 20 of the 27 proteins were correctly identified. Importantly, correct identifications showed unambiguous "correct" score patterns. While incorrect protein identifications also showed distinctive score patterns, indicating that protein must be identified by other means. These techniques allow large-scale screening of the protein complement of simple organisms, or tissues in normal and disease states. The computer program described here is accessible via the World Wide Web at URL address (http:@expasy.hcuge.ch/). 相似文献