全文获取类型
收费全文 | 832篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 29篇 |
综合类 | 2篇 |
化学工业 | 162篇 |
金属工艺 | 16篇 |
机械仪表 | 13篇 |
建筑科学 | 9篇 |
能源动力 | 10篇 |
轻工业 | 74篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 85篇 |
一般工业技术 | 166篇 |
冶金工业 | 223篇 |
原子能技术 | 12篇 |
自动化技术 | 47篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 12篇 |
2020年 | 2篇 |
2019年 | 7篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 15篇 |
2013年 | 27篇 |
2012年 | 21篇 |
2011年 | 36篇 |
2010年 | 21篇 |
2009年 | 23篇 |
2008年 | 27篇 |
2007年 | 35篇 |
2006年 | 26篇 |
2005年 | 17篇 |
2004年 | 22篇 |
2003年 | 19篇 |
2002年 | 37篇 |
2001年 | 32篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 92篇 |
1997年 | 51篇 |
1996年 | 38篇 |
1995年 | 20篇 |
1994年 | 15篇 |
1993年 | 20篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 16篇 |
1974年 | 3篇 |
1972年 | 5篇 |
排序方式: 共有851条查询结果,搜索用时 0 毫秒
141.
Kazunori Komatani Shinichi Ueno Tatsuya Kawahara Hiroshi G. Okuno 《User Modeling and User-Adapted Interaction》2005,15(1-2):169-183
We address the issue of appropriate user modeling to generate cooperative responses to users in spoken dialogue systems. Unlike
previous studies that have focused on a user’s knowledge, we propose more generalized modeling. We specifically set up three
dimensions for user models: the skill level in use of the system, the knowledge level about the target domain, and the degree of urgency. Moreover, the models are automatically derived by decision tree learning using actual dialogue data collected by the system.
We obtained reasonable accuracy in classification for all dimensions. Dialogue strategies based on user modeling were implemented
on the Kyoto City Bus Information System that was developed at our laboratory. Experimental evaluations revealed that the
cooperative responses adapted to each subject type served as good guides for novices without increasing the duration dialogue
lasted for skilled users. 相似文献
142.
1,3-Dipalmitoyl-2-oleoyl-sn-glycerol (POP) and 1,2-dioleoyl-3-palmitoyl-rac-glycerol (OOP) are two major molecular species that account for roughly half of the total triacylglycerols in palm oil. The
binary phase behavior of a POP/OOP mixture plays an important role in the crystallization of palm oil. We conducted thermodynamic
and kinetic studies of OOP and its mixtures with POP using differential scanning calorimetry and X-ray diffraction with a
conventional generator and synchrotron radiation. We found that OOP has two polymorphs, α as a metastable form and β′ as the
most stable form, and that the two forms are stacked in a triple-chain-length structure. The POP/OOP mixtures exhibited immiscible
eutectic natures in both their metastable and their most stable states, in contrast to POP/1,2-dipalmitoyl-3-oleoyl-rac-glycerol and POP/1,3-dioleoyl-2-palmitoyl-sn-glycerol mixtures, in which molecular compounds of a double-chain-length structure were formed. A time-resolved synchrotron
radiation X-ray diffraction study undertaken during the cooling and heating processes indicated that the α and β′ forms of
the POP and OOP fractions crystallized and melted in separate manners, and that crystallization of the β′ form and the polymorphic
transformation from α to β′ of POP and OOP are promoted in the presence of another component. The absence of molecular compound
crystals in the binary mixtures of POP/OOP is explained by taking into account the molecular interactions of acyl chain packing,
glycerol conformation, and methyl end stacking, among which glycerol conformation appeared to be most influential. 相似文献
143.
Direct measurement by high-performance size exclusion chromatography with fluorescence detection was applied to the characterization of humic substances in river waters from the Kuji River system, which runs through forest hills and an agricultural plain in Japan. The monitoring wavelength of excitation 320 nm and emission 430 nm corresponds to the fluorescence maxima for aquatic fulvic acid. Chromatograms of the river waters showed four peaks; each peak position was in good agreement among these samples. Peak height ratios for the samples from the upstream Kuji River and its tributaries were different from those of the midstream and downstream sections of the Kuji River, which may reflect differences in the characteristics of humic substances and other organic materials supplied from soil to river. 相似文献
144.
高分辨率数码相机的出现为砂土模型试验变形场非接触量测法的研究开发提供了一条简便经济而且实用的途径,在模型试验观测面上,不再需要布置嵌入式量测标志点或描画网格,直接用数码相机在试验各阶段拍摄照片,然后对照片序列进行图像相关分析,即可得出模型试验的变形场分布。利用图像匹配技术追踪模型上点的位移,借用FEM常用的等参单元的概念进行图像校准和应变计算,采用双线性插值技术可以实现微小变形量测,并提出同时用平移和旋转搜索方法,以适应砂土模型的变形特点。精度检验试验结果表明,一个像素以下的平移量测标准方差达到0.19个像素,数值试验表明,15°旋转刚体变形量测,非旋转搜索和旋转搜索的标准方差分别为0.49和0.08个像素。最后给出一个在砂土地基承载力离心机模型试验中的应用实例,分析结果包含砂土模型位移场、最大剪应变场和体积应变场的分布图。结果表明这一方法使得砂土模型局部化变形、剪切带和渐进破坏过程的量化分析成为可能。 相似文献
145.
146.
A lithium-encapsulated fullerenol Li@C60(OH)18, as an example of a polar solvent-soluble endohedral fullerene derivative, has been synthesized and fully characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, UV spectroscopy, electron spin resonance (ESR) spectroscopy, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS), elemental analysis, thermogravimetric analysis, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and the particle size was determined using the induced grating (IG) method, and scanning probe microscopy. The encapsulated Li+ was clearly detected by 7Li NMR at very high field in the range −15 to −19 ppm, an intermediate lithium-encapsulated fullerenol was detected by MALDI-TOF-MS, and the molar ratio of lithium-encapsulated fullerenol to empty fullerenol was quantitatively determined to be 12:88 by ICP-AES. The solid-state ESR and particle size measurements using the IG method showed the characteristic anionic behavior with no external counter cations, in what can be called a “cation-encapsulated anion nanoparticle”, revealing the drastic differences between its properties and those of empty C60(OH)16. 相似文献
147.
Amphiphilic poly(amido amine) (PAMAM) dendrons were immobilized on the surface of silica particles, following the solid phase strategy. PAMAM dendrons were constructed by the repetitive feeding of methyl acrylate and ethylenediamine as the monomers. The peripheral functionalization of amine to long alkyl ends generated the amphiphilic PAMAM dendron on the silica surface. These amphiphilic dendron-modified silica particles were applicable as new packing materials for ultrahigh pressure liquid chromatography. 相似文献
148.
M. Jeong M. Song T. Ueno T. Mizusaki A. Matsubara S. Lee 《Journal of Low Temperature Physics》2010,158(3-4):659-665
We report NMR measurements of transverse relaxation rate 1/T 2 of the 31P nuclear spins in metallic Si:P (concentration of dopant P, n=18×1018 and 56×1018 cm?3) at temperatures between 45 mK and 5 K in a magnetic field of 7 T. Above 1.4 K, 1/T 2 is constant independent of temperature as well as concentration and is determined by magnetic dipolar interaction between the 31P and 29Si nuclear spins. As temperature decreases below 1.4 K, 1/T 2 increases over the dipolar-determined value by an order of magnitude and levels off around 0.6 K. The concentration dependence of 1/T 2 at low temperatures suggests that 1/T 2 below 1.4 K is determined by the coupling between the 31P nuclear spins. We understand 1/T 2 at low temperatures originates from the RKKY interaction. We explain the temperature dependence of 1/T 2 between 0.6 K and 1.4 K by the motional-narrowing expression of 1/T 2 with a temperature-dependent correlation time of the fluctuating local field due to the RKKY interaction. 相似文献
149.
The changes in the morphological structure and proteoglycan (PGs) extractability of the intramuscular connective tissues from bovine skeletal muscle exposed to high pressure (100~400 MPa) were investigated and compared to those in muscle during ageing. SDS-PAGE profiles of the PGs were also studied. During ageing, structural changes in the endomysium and perimysium occured, and disruption of the honeycomb-like structure of endomysium was observed. In the pressurized muscle, deformation of the honeycomb-like structure of endomysium was accelerated with increase of pressure applied to the muscle, and disruption of endomysium was observed in several places in the muscle pressurized at 400 MPa. Changes in the extractability of PGs were not observed in the pressurized muscle, whereas the extractability of PGs decreased with ageing. Changes in the density of the main component in the PGs with molecular mass of more than 3000 kDa on the SDS-PAGE were not observed in the PGs from the pressurized muscle, whereas the density of this band gradually decreased during the ageing. The decrease in the amounts of PGs extracted from the aged muscle seems to be due to degradation of the PGs into small dialysable molecules. From the results, it seems that high pressure treatment has some different effects on intramuscular connective tissue to ageing. ? 相似文献
150.
Noriyasu Kobayashi Souichi Ueno Satoshi Nagai Makoto Ochiai Noboru Jimbo 《Nuclear Engineering and Design》2011,241(12):4643-4648
We confirmed the defect detection performances of the remote field eddy current testing (RFECT) in order to inspect the helical-coil-type double wall tube steam generator (DWTSG) with the wire mesh layer for the new small fast reactor 4S (Super-Safe, Small and Simple). As the high sensitivity techniques, we tried to increase the direct magnetic field intensity in the vicinity of the inner wall of the tube and decrease the direct magnetic field around the central axis of the tube using the exciter coil with the flux guide made of the iron–nickel alloy. We adopted the horizontal type multiple detector coils with the flux guides arrayed circumferentially to enhance the sensitivity of the radial component. According to the experimental results, the output voltage of the detector coil in the region of indirect magnetic field increased more than 100 times by the application of the exciter and detector coils with the flux guides. Finally, we were able to detect the small hole defect of 1 mm in diameter and 20% of the outer tube thickness in depth over the wire mesh layer by the adoption of the exciter coil and horizontal type multiple detector coils with the flux guides. We also confirmed that the RFECT probe is useful for detecting thinning defects. These experimental results indicated that there is the possibility that we can inspect the double wall tube with the wire mesh layer using the RFECT. 相似文献