全文获取类型
收费全文 | 1553篇 |
免费 | 30篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 84篇 |
综合类 | 2篇 |
化学工业 | 369篇 |
金属工艺 | 30篇 |
机械仪表 | 27篇 |
建筑科学 | 16篇 |
能源动力 | 49篇 |
轻工业 | 127篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 208篇 |
一般工业技术 | 228篇 |
冶金工业 | 254篇 |
原子能技术 | 38篇 |
自动化技术 | 149篇 |
出版年
2023年 | 8篇 |
2022年 | 19篇 |
2021年 | 27篇 |
2020年 | 14篇 |
2019年 | 20篇 |
2018年 | 12篇 |
2017年 | 20篇 |
2016年 | 27篇 |
2015年 | 21篇 |
2014年 | 38篇 |
2013年 | 75篇 |
2012年 | 61篇 |
2011年 | 81篇 |
2010年 | 55篇 |
2009年 | 67篇 |
2008年 | 61篇 |
2007年 | 60篇 |
2006年 | 64篇 |
2005年 | 42篇 |
2004年 | 49篇 |
2003年 | 46篇 |
2002年 | 40篇 |
2001年 | 34篇 |
2000年 | 41篇 |
1999年 | 41篇 |
1998年 | 137篇 |
1997年 | 72篇 |
1996年 | 44篇 |
1995年 | 44篇 |
1994年 | 27篇 |
1993年 | 33篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 20篇 |
1989年 | 14篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 17篇 |
1985年 | 14篇 |
1984年 | 13篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1977年 | 10篇 |
1976年 | 14篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1932年 | 2篇 |
排序方式: 共有1585条查询结果,搜索用时 15 毫秒
1.
Nayve R. Fujii M. Fukugawa A. Takeuchi T. Murata M. Yamada Y. Koyanagi M. 《Journal of microelectromechanical systems》2004,13(5):814-821
This paper describes the fabrication and characterization of a thermal ink jet (TIJ) printhead suitable for high speed and high-quality printing. The printhead has been fabricated by dicing the bonded wafer, which consists of a bubble generating heater plate and a Si channel plate. The Si channel plate consists of an ink chamber and an ink inlet formed by KOH etching, and a nozzle formed by inductively couple plasma reactive ion etching (ICP RIE). The nozzle formed by RIE has squeezed structures, which contribute to high-energy efficiency of drop ejector and, therefore, successful ejection of small ink drop. The nozzle also has a dome-like structure called channel pit, which contributes to high jetting frequency and high-energy efficiency. These two wafers are directly bonded using electrostatic bonding of full-cured polyimide to Si. The adhesive-less bonding provided an ideal shaped small nozzle orifice. Use of the same material (Si substrate) in heater plate and channel plate enables the fabrication of high precision long printhead because no displacement and delamination occur, which are caused by the difference in thermal expansion coefficient between the plates. With these technologies, we have fabricated a 1" long printhead with 832 nozzles having 800 dots per inch (dpi) resolution and a 4 pl. ink drop volume. 相似文献
2.
Network information criterion-determining the number of hiddenunits for an artificial neural network model 总被引:6,自引:0,他引:6
The problem of model selection, or determination of the number of hidden units, can be approached statistically, by generalizing Akaike's information criterion (AIC) to be applicable to unfaithful (i.e., unrealizable) models with general loss criteria including regularization terms. The relation between the training error and the generalization error is studied in terms of the number of the training examples and the complexity of a network which reduces to the number of parameters in the ordinary statistical theory of AIC. This relation leads to a new network information criterion which is useful for selecting the optimal network model based on a given training set. 相似文献
3.
Hashimoto J. Yoshida I. Murata M. Katsuyama T. 《Quantum Electronics, IEEE Journal of》1997,33(1):66-70
In this paper, we studied the aging time dependence of the catastrophic optical damage (COD) failure of an Al-free uncoated 0.98-μm GaInAs-GaInP strained quantum-well laser with an injection current as a parameter. Based on the stress-strength model, we first investigated experimentally the dependence of the critical power level (CPL) at which COD would take place upon the aging time. Then applying a statistical treatment to this result, we found for the first time that CPL data at each aging time could be considered to distribute according to the Weibull statistics, and the decrease rate of the CPL with the aging time depended very strongly on the injection current. Finally, using the relationship between the decrease rate of the CPL with the aging time and the current, we predicted roughly the time of a COD failure occurrence for both large and small current cases. As a result, we clarified that for our Al-free uncoated 0.98-μm laser, a COD failure became a fatal problem in the case of a large-current (high-power) operation 相似文献
4.
Masatsune Kato Takaaki Aoki Takashi Noji Yasuhiro Ono Yoji Koike Tomoyuki Hikita Yoshitami Saito 《Journal of Superconductivity and Novel Magnetism》1994,7(1):37-38
We have investigated the relation between the crystal structure and superconductivity in La1.9Bi0.1CuO4+δ , in which the phase separation observed in La2CuO4+δ is suppressed. A phase diagram in theT?δ plane is given for La1.9Bi0.1CuO4+δ with excess oxygen. For very smallδ values, the crystal structure is orthorhombic, and an orthorhombic-tetragonal phase transition occurs markedly atδ ~ 0.03 in the measured temperature range between 13 and 293 K. Superconductivity is observed in the range of 0.04<δ<0.11. This is clear evidence thathigh-T c superconductivity also appears in the tetragonal phase. 相似文献
5.
F Chen M Murata Y Hiraku N Yamashita S Oikawa S Kawanishi 《Canadian Metallurgical Quarterly》1998,29(3):197-205
We have previously reported that long-term priming of human polymorphonuclear neutrophilic granulocytes (PMN) with interferon-gamma (IFN-gamma) increased the fMLP-stimulated calcium influx. We now show that also after short-term incubation with IFN-gamma, PMN calcium metabolism is modulated. Single adherent cells in three different calcium-containing buffers (high, normal, and low [Ca2+]) were stimulated with the bacterial peptide fMLP or the Ca-ATPase inhibitor thapsigargin (Tg) after about 5 min preincubation with IFN-gamma. The results of this protocol indicated that IFN-gamma increases both calcium influx and calcium sequestration. Store dependent Ca2+ influx, directly measured on readdition of calcium to Tg-treated cells incubated in EGTA buffer, was significantly enhanced in IFN-gamma-treated cells. This effect of IFN-gamma was enhanced by the tyrosine kinase inhibitor herbimycin A. Strikingly, in low extracellular calcium concentrations, IFN-gamma induced calcium transients in 20%-60% of the cells. The proportion of PMN responding with Ca2+ transients increased with decreasing extracellular calcium concentration. Average lagtime from addition of IFN-gamma to a response that could be measured was 7.3 sec, and average increase in [Ca2+] above the basal level was 790 nM. These IFN-gamma-induced transients could not be depressed by herbimycin A. Thus, IFN-gamma can increase capacitative calcium influx, induce calcium transients, and possibly affect calcium sequestration in human PMN. 相似文献
6.
A high-speed selector module has been developed. It is constructed from a selector IC mounted in a ceramic package, a power supply unit, phase shifters, and coaxial cables. The IC was designed using LSCFL and fabricated with 0.2 mu m gate length GaAs MESFETs. The selector module operated above 25 Gbit/s. It is expected to be applied to high-speed IC measurements.<> 相似文献
7.
Tadashi Hano Michiaki Matsumoto Takahisa Kawazu Takaaki Ohtake 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,62(1):60-63
The extraction equilibria of various di- and tripeptides with di-2-ethylhexylphosphoric acid (D2EHPA) were studied at low pH values. The complex extracted to organic phase consisted of one molecule of peptide and two molecules of D2EHPA dimer. The extraction constants of the peptides correlated well with the distribution coefficients of peptides between 1-octanol and water, which is a measure of hydrophobicity. The permeation rates of peptides through an emulsion liquid membrane were examined by using D2EHPA as a carrier, Span 80 as an emulsifier and kerosene as a diluent. The rates varied considerably with peptide type, depending upon the hydrophobicity. 相似文献
8.
A 66-kV network generally is grounded through a neutral grounding resistor. In this network a single-phase ground-fault current is limited to as small as 100 to 400 A. There are parallel four-circuit transmission lines mounted on the same tower in the 66-kV network. In such transmission lines, the load and the fault currents could induce circulating current that flows through the lines. Since the circulating current has zero-phase-sequence and negative-phase-sequence components, it could cause unwanted operation of a balance ground relay using zero-phase-sequence current. However, it is difficult to compensate for the circulating current by the conventional vector compensation scheme. This paper presents a new balance ground relay to deal with the circulating current. In the relay from the ground-fault inception until first tripping, the difference current Δ3I2d of negative-phase-sequence current 3I2d of the differential current between two protected lines is used as an input current. The Δ3I2d is the difference current of 3I2d between, before and during faults. After the first tripping, the difference current of positive-phase-sequence load current and zero-phase-sequence current of the forementioned differential current are used as an input current. Consequently, a higher sensitivity of the ground-fault protection for these lines has been achieved. The correct operation of the new balance ground relay was confirmed when a single-phase-ground-fault occurred in the parallel four-circuit transmission lines, to which the relay is applied. 相似文献
9.
Karen S. Servilla Antonios H. Tzamaloukas Charles Carter Glen H. Murata 《Hemodialysis international. International Symposium on Home Hemodialysis》2002,6(1):35-39
We developed a composite compliance index as the sum of the compliance scores for interdialytic weight gain (IDWG), pre‐dialysis serum potassium and phosphorus concentrations (each scored from zero to 3, with 3 indicating the poorest compliance), and skipping hemodialysis sessions (scored from zero to 9, with 9 indicating the poorest compliance). We used this composite score to prospectively evaluate compliance in 25 prevalent hemodialysis patients over a period of 1 year. We then followed these patients for another 3.5 years. The patients studied were divided into two groups: group A (poor compliance) consisted of 9 subjects with composite score ≥ 9 (13.2 ± 3.2); group B (better compliance) consisted of 16 subjects with composite score < 9 (4.7 ± 1.8). Age, duration of hemodialysis, and frequency of diabetes mellitus did not differ between the groups. Group A contained higher fractions of subjects with history of alcoholism (66.7% vs 12.5%, p = 0.010), other substance addiction (44.4% vs 0%, p = 0.010), and severe psychosocial problems (88.9% vs 18.8%, p = 0.002). Mean survival from the beginning of observation, estimated by actuarial life‐table survival analysis, was 1.19 years in group A and 2.60 years in group B (p = 0.0265). A composite compliance index incorporating domains indicating adherence to diet, medications, and dialysis schedule identified other behavioral problems in poorly compliant patients. Hemodialysis patients characterized by this composite index as poorly compliant had shortened survival. 相似文献
10.
Yuji Oie Tatsuya Suda Masayuki Murata Hideo Miyahara 《International Journal of Satellite Communications and Networking》1991,9(5):285-303
One of the most promising approaches for high speed networks for integrated service applications is fast packet switching, or ATM (asynchronous transfer mode). ATM can be characterized by very high speed transmission links and simple, hard-wired protocols within a network. To match the transmission speed of the network links, and to minimize the overhead due to the processing of network protocols, the switching of cells is done in hardware switching fabrics in ATM networks. A number of designs have been proposed for implementing ATM switches. Although many differences exist among the proposals, the vast majority of them are based on self-routeing multistage interconnection networks. This is because of the desirable features of multi-stage interconnection networks such as self-routeing capability and suitability for VLSI implementation. Existing ATM switch architectures can be classified into two major classes: blocking switches, where blockings of cells may occur within a switch when more than one cell contends for the same internal link, and non-blocking switches, where no internal blocking occurs. A large number of techniques have also been proposed to improve the performance of blocking and non-blocking switches. In this paper, we present an extensive survey of the existing proposals for ATM switch architectures, focusing on their performance issues. 相似文献