全文获取类型
收费全文 | 1738篇 |
免费 | 47篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 107篇 |
综合类 | 6篇 |
化学工业 | 413篇 |
金属工艺 | 75篇 |
机械仪表 | 38篇 |
建筑科学 | 34篇 |
能源动力 | 74篇 |
轻工业 | 86篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
无线电 | 132篇 |
一般工业技术 | 307篇 |
冶金工业 | 317篇 |
原子能技术 | 67篇 |
自动化技术 | 125篇 |
出版年
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 41篇 |
2020年 | 26篇 |
2019年 | 27篇 |
2018年 | 23篇 |
2017年 | 13篇 |
2016年 | 34篇 |
2015年 | 24篇 |
2014年 | 37篇 |
2013年 | 78篇 |
2012年 | 75篇 |
2011年 | 88篇 |
2010年 | 56篇 |
2009年 | 70篇 |
2008年 | 93篇 |
2007年 | 62篇 |
2006年 | 55篇 |
2005年 | 56篇 |
2004年 | 47篇 |
2003年 | 44篇 |
2002年 | 51篇 |
2001年 | 39篇 |
2000年 | 43篇 |
1999年 | 48篇 |
1998年 | 139篇 |
1997年 | 83篇 |
1996年 | 47篇 |
1995年 | 27篇 |
1994年 | 34篇 |
1993年 | 40篇 |
1992年 | 18篇 |
1991年 | 15篇 |
1990年 | 21篇 |
1989年 | 11篇 |
1988年 | 21篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 22篇 |
1984年 | 18篇 |
1983年 | 11篇 |
1982年 | 21篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 13篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 6篇 |
排序方式: 共有1790条查询结果,搜索用时 15 毫秒
131.
132.
Thecautious scheduler, recently proposed for the concurrency control of database systems, never resorts to abortions or rollbacks for the purpose of concurrency control. The comprehensive performance evaluation study among different cautious schedulers and conventional non-cautious schedulers, however, has not yet been attempted. In this paper, we consider five scheduling algorithms and investigate their performance by means of simulation studies. Two of these algorithms are non-cautious; that is, thetwo-phase locking algorithm (2PL) (the most popular transaction scheduling algorithm in practical systems) and theconflict serializable algorithm (CSR) (a typical scheduling algorithm among those not using a locking mechanism; also calledD-serializable algorithm, conflict preserving serializable algorithm, orWW-serializable algorithm). The others are cautious scheduling algorithms modified from the above2PL andCSR; that is,cautious two-phase locking algorithm (C2PL), exclusive preclaimed two-phase locking algorithm (EP2PL), andcautious conflict serializable algoritm (CCSR). The results demonstrate the superiority of the cautious conflict serializable algorithm over the conventional two-phase locking algorithm, especially in the on-line system environment.This work was supported in part by the Ministry of Education, Science and Culture of Japan under Scientific Research Grant-in-Aid and in part by the Advancd Systems Foundations of British Columbia, Canada. 相似文献
133.
Cooking up an interactive olfactory game display. 总被引:2,自引:0,他引:2
Takamichi Nakamoto Shigeki Otaguro Masashi Kinoshita Masahiko Nagahama Keita Ohinishi Taro Ishida 《Computer Graphics and Applications, IEEE》2008,28(1):75-78
It's long been possible to give users outside an actual environment that environment's visual and auditory information and thus contribute to establishing presence. However, we've yet to establish much presence when users require olfactory information - such as in environments focused on foods, flowers, perfumes, or, in some cases, more offensive smells. Recently, several VR researchers have become interested in olfaction and olfactory displays that present smells in virtual environments (VEs). In this article, we describe our interactive olfactory display. One of our development goals is to confirm the assumption that users' interactions with the system increases presence. Thus, we used our interactive olfactory display to develop a cooking game in collaboration with electronic engineers and artists. 相似文献
134.
Yoshino M. Kaneko S. Taniguchi T. Miki N. Kumozaki K. Imai T. Yoshimoto N. Tsubokawa M. 《Lightwave Technology, Journal of》2008,26(8):962-970
In order to relax the limitation of the number of multiplexed signal lights caused by beat noise between signal lights, we investigate the applicability of a heterodyne detection technique to a spectral amplitude coding optical code division multiple access scheme. In this investigation, for the first time, we found analytically that the optical frequency chips that form parts of the signal and local lights require uniform phase differences even for envelope detection. We also confirm this requirement and our theoretical analysis experimentally. 相似文献
135.
Miyake J. Maeda T. Nishimichi Y. Katsura J. Taniguchi T. Yamaguchi S. Edamatsu H. Watari S. Takagi Y. Tsuji K. Kuninobu S. Cox S. Duschatko D. MacGregor D. 《Solid-State Circuits, IEEE Journal of》1990,25(5):1199-1206
A 1-million transistor 64-b microprocessor has been fabricated using 0.8-μm double-metal CMOS technology. A 40-MIPS (million instructions per second) and 20-MFLOPS (million floating-point operations per second) peak performance at 40 MHz is realized by a self-clocked register file and two translation lookaside buffers (TLBs) with word-line transition detection circuits. The processor contains an integer unit based on the SPARC (scalable processor architecture) RISC (reduced instruction set computer) architecture, a floating-point unit (FPU) which executes IEEE-754 single- and double-precision floating-point operations a 6-KB three-way set-associative physical instruction cache, a 2-KB two-way set-associative physical data cache, a memory management unit that has two TLBs, and a bus control unit with an ECC (error-correcting code) circuit 相似文献
136.
Yuki Matsushita Junko Taniguchi Ryo Toda Hiroki Ikegami Taku Matsushita Mitsunori Hieda Nobuo Wada 《Journal of Low Temperature Physics》2008,150(3-4):342-346
We have studied heat capacities of 4He adsorbed in straight nanopores 1.8, 2.2, and 2.8 nm in diameter. Heat capacities of the 4He fluid film on the solid layer at 0.08–0.4 K show power laws close to T in 1.8 nm pores, close to T
2 in 2.8 nm pores, and a crossover from T to T
2 with increasing temperature in 2.2 nm pores. These heat capacities are explained by a model assuming a phonon dispersion
with continuous one-dimensional (1D) states in the axial direction and discrete energy levels in the azimuthal direction.
By fitting experimental data to the model, the phonon velocity along the pore axis and the energy gap for propagation in the
cross section are derived. At temperatures sufficiently lower than the energy gap, where the thermal wave length of phonons
is much longer than the effective pore diameter, the 4He fluid films show a T-linear heat capacity of 1D phonons propagating only along the pore axis. At higher temperatures, a 1D-2D crossover of phonons
occurs.
相似文献
137.
Chigusa S. Maeda H. Taniguchi Y. Hayakawa N. Okubo H. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1999,6(3):385-392
We have been studying quench-induced `dynamic' breakdown characteristics of LHe and have already found that the electrical insulation performance of LHe was degraded drastically by the thermal bubble disturbance due to quench of superconductors. In this paper, in order to improve the insulation performance of LHe under quench conditions, we measured dynamic breakdown and prebreakdown characteristics of pressurized LHe. Experimental results revealed that breakdown voltage of LHe under quench conditions at 0.2 MPa was greatly improved, reaching 2 to 4× compared with that at atmospheric pressure under both uniform and non-uniform electric fields. Moreover, for practical and efficient insulation design of superconducting power apparatus, we investigated the dynamic breakdown voltage of LHe as functions of pressure and gap length 相似文献
138.
Makoto Wakabayashi Takayuki Kohno Tokutaro Kimura Satoshi Tamura Masahiko Endoh Satoru Ohnishi Toshikatsu Nishioka Yoshikatsu Tanaka Toshitaka Kanai 《应用聚合物科学杂志》2007,106(2):1398-1404
Many additives are commercially used to add more favorable qualities to films. The bleeding process by which the additive in a film comes to the surface is considered. A new bleeding model of additives in a polypropylene film under atmospheric pressure was investigated. Solubility and diffusion are found to be important for explaining this bleeding process. It was found that the experimental results were explained more precisely by assuming a two‐step transport process between the crystalline regions and the amorphous ones. The solubilities and diffusion coefficients of UV‐stabilizers such as 2‐(2H‐benzotriazol‐2‐yl)‐4‐(1,1,3,3‐tetramethylbutyl)phenol and 2‐(2H‐benzotriazol‐2‐yl)‐4‐methylphenol were determined at 40°C. The difference between the saturation solubilities and the diffusion coefficients of UV‐stabilizers was discussed by comparing with the results of molecular dynamics (MD) simulation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
139.
The oxidation kinetics of cold-rolled Remko iron coupons in purified oxygen at atmospheric pressure in the temperature range 973–1173K and the morphologies of both oxide scales and subtrate surfaces were studied using thermogravimetric, metallographic and scanning electron-microscope techniques.Parabolic oxidation rate constants were found to decrease after initial varying periods of constancy, an effect believed to be due to void formation at the wüstite/iron interfaces by the coalescence of vacancies. The observed subsequent recoveries of the values of the rate constants were considered to be due to an increase in oxide growth stresses to values large enough to cause appreciable plastic flow of oxide, thereby decreasing the number of interfacial voids.The extent of the deviations from the initial values of the rate constants decreased as the oxidation temperature was increased and this was considered to be due to the enhanced plasticity of the scale and increased rate of stress generation which favoured the elimination of the interfacial voids.In the temperature range 973–1073K, there were periods in which logarithmic growth relationships were observed, the mechanism being similar to that suggested by Evans, and involving a continuous increase in the number of interfacial voids. 相似文献
140.