全文获取类型
收费全文 | 198篇 |
免费 | 1篇 |
专业分类
电工技术 | 30篇 |
化学工业 | 17篇 |
机械仪表 | 1篇 |
建筑科学 | 1篇 |
能源动力 | 1篇 |
轻工业 | 3篇 |
无线电 | 32篇 |
一般工业技术 | 40篇 |
冶金工业 | 56篇 |
自动化技术 | 18篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2016年 | 1篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 5篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 22篇 |
1997年 | 13篇 |
1996年 | 12篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1967年 | 2篇 |
排序方式: 共有199条查询结果,搜索用时 46 毫秒
21.
Hara T. Fukuda K. Kanazawa K. Shibata N. Hosono K. Maejima H. Nakagawa M. Abe T. Kojima M. Fujiu M. Takeuchi Y. Amemiya K. Morooka M. Kamei T. Nasu H. Chi-Ming Wang Sakurai K. Tokiwa N. Waki H. Maruyama T. Yoshikawa S. Higashitani M. Pham T.D. Yupin Fong Watanabe T. 《Solid-State Circuits, IEEE Journal of》2006,41(1):161-169
An 8-Gb multi-level NAND Flash memory with 4-level programmed cells has been developed successfully. The cost-effective small chip has been fabricated in 70-nm CMOS technology. To decrease the chip size, a one-sided pad arrangement with compacted core architecture and a block address expansion scheme without block redundancy replacement have been introduced. With these methods, the chip size has been reduced to 146 mm/sup 2/, which is 4.9% smaller than the conventional chip. In terms of performance, the program throughput reaches 6 MB/s at 4-KB page operation, which is significantly faster than previously reported and very competitive with binary Flash memories. This high performance has been achieved by the combination of the multi-level cell (MLC) programming with write caches and with the program voltage compensation technique for neighboring select transistors. The read throughput reaches 60 MB/s using 16I/O configuration. 相似文献
22.
I Chiba M Muthumala Y Yamazaki A Uz Zaman T Iizuka A Amemiya T Shibata H Kashiwazaki C Sugiura H Fukuda 《Canadian Metallurgical Quarterly》1998,77(6):839-842
The PCR copy of the ribR gene of Bacillus subtilis was subcloned in Escherichia coli cells under the control of the phage T7 inducible promoter. The polypeptide of 26 kDa corresponding to the 690-bp gene is the product of the ribR gene. The protein encoded by the ribR gene is flavokinase, and the riboflavin-reduced form is the substrate for it. 相似文献
23.
24.
If we are to significantly increase the transmission speed of optical networks, the impact of higher order dispersion must be clarified. This paper gives general expressions that describe pulse broadening due to even and odd higher order dispersion in a single-mode fiber. The intrinsic impulsive responses for even order dispersion (beyond the second order) are characterized by symmetrical waveforms with long trailing skirts, whereas the responses for odd orders show asymmetrical strongly oscillating waveforms. The transmission limits are also analytically obtained for each higher nth order that induces intersymbol interference. Transmission lengths are limited by the factor of 1/B0n where B0 is the bit rate and n is the dispersion order 相似文献
25.
26.
27.
28.
Sueyoshi T. Naono H. Kawanami M. Amemiya M. Hayama H. 《IEEE transactions on magnetics》1984,20(1):42-44
The process of formation of iron fine particles from goethite microcrystals was investigated by means of powder X-ray diffraction, gas adsorption, and electron microscopy. In the first process, microporous hematite particles were prepared by decomposing goethite particles. The pores formed in hematite particles were slit-shaped (width : 0.9 nm). In the second process, microporous hematite particles were reduced at 250-350°C under the flow of hydrogen gas, and the reduction degree R (%) was determined. In the sample of R=8%, mesopores of 4 - 8 nm were formed by aggregation of slit-shaped micropores, but the skeleton of acicular particles was not significantly altered. With the progress in reduction, a number of crystallites were formed in the parent particles together with growth of pore size. In the sample of R=72%, the crystallites were separated from the parent particles. Finally, the separated crystallites sintered to give granular iron particles having low coercivity of 375 Oe. It was found that alumina or silica gel coated on the surface of goethite particles was remarkably effective for preventing the separation and sintering of crystallites formed in the parent particles. The silica-coated iron fine particles consisting of the crystallites which were as large as single domain particles showed excellent acicular shape and high coercivity of 1600 - 1700 Oe. 相似文献
29.
When a p-n junction of semiconductor (with bandgap energy Eg) is illuminated by light beam (with photon energy hv) in the condition of Eg>hv, such as in Ge p-n junction illuminated by CO2 laser beam, an electromotive force (emf) was induced between the terminals of the p-n junction, which indicated the opposite polarity to the ordinary photovoltaic effect like a solar cell. Such an anomalous photovoltaic phenomenon was explained by an optically excited hot carrier effect, through the following experiment with electrical excitation. Using a rod of n- or p-type Ge with a p-n junction at the surface of its center and an ohmic contact at each terminal of the rod, the same kind of phenomena was observed when electric field is applied along the length of the rod. The perpendicularly induced voltage or current had the same polarity instead of the reverse change of the applied electric field, and increases with increasing the applied field strength. The perpendicularly induced emf was caused by warm or hot carriers crossing the potential barrier of the p-n junction, which is very sensitive to the departure from thermally equilibrium velocity distribution of carriers. 相似文献
30.
In interphase eukaryotic cells, molecular transport between the cytoplasm and the nucleus is mediated by the nuclear pore complex (NPC), which perforates the double-membraned nuclear envelope (NE). Local permeability of the NE at large intact nuclei (approximately 400 microm in diameter) isolated from Xenopus laevis oocytes was studied by scanning electrochemical microscopy (SECM). Steady-state tip current versus tip-nucleus distance curves (approach curves) were measured with 10- and 2-microm-diameter Pt disk microelectrodes at the nuclei in isotonic buffer solutions containing redox-active molecules. The approach curves in the normalized form are independent of the tip diameter, indicating diffusion-limited membrane transport of the redox molecules. SECM chronoamperometry demonstrated that a decrease in the steady-state tip current at short tip-nucleus distances is due to smaller diffusion coefficients and concentrations of the redox molecules in the nucleus than those in the buffer solution. The experimental approach curves fit very well with theoretical ones for freely permeable membranes, yielding the NE permeability to the molecules that is at least 2 orders of magnitude larger than permeability of bilayer lipid membranes and cell membranes. This result indicates that passive transport of the redox molecules across the NE is facilitated by open NPC pores. The flux of the redox molecules sustainable by a single NPC channel (>9.8 x 10(6) molecules per NPC per second) and the diameter of the channel pore (>15 nm) were estimated from the SECM data by assuming the NE as an array of nanometer-sized NPC pores. The effects of the redox molecules on the nucleus and the NPC function were examined by studying signal-mediated nuclear import of rhodamine-labeled bovine serum albumin with and without nuclear localization signals by fluorescence microscopy. 相似文献