全文获取类型
收费全文 | 458篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 250篇 |
晶体学 | 2篇 |
力学 | 6篇 |
数学 | 2篇 |
物理学 | 95篇 |
无线电 | 111篇 |
出版年
2022年 | 2篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 2篇 |
2013年 | 21篇 |
2012年 | 20篇 |
2011年 | 14篇 |
2010年 | 14篇 |
2009年 | 8篇 |
2008年 | 25篇 |
2007年 | 25篇 |
2006年 | 20篇 |
2005年 | 26篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2002年 | 17篇 |
2001年 | 14篇 |
2000年 | 15篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 17篇 |
1989年 | 11篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1972年 | 1篇 |
1971年 | 4篇 |
1967年 | 2篇 |
排序方式: 共有466条查询结果,搜索用时 0 毫秒
41.
Kawashima S. Endo T. Yamamoto A. Nakabayashi K. Nakazawa M. Morita K. Aoki M. 《Solid-State Circuits, IEEE Journal of》2002,37(5):592-598
In this sensing technique, pMOS charge transfer maintains the bitline level near the GND when the plate line goes high. It gives 0.5-V higher readout voltages across the cell capacitors and enables a 0.4-V higher differential amplitude in a 512-cell per bitline structure compared with the conventional high-impedance bitline sensing technique. Using the shifted bias plate line layout, only eight cells and eight sense amplifiers per cell mat are activated, and simulations show 8.06 mW at 3 V and 5 MHz, which is about the same power consumption as the conventional device 相似文献
42.
A simplified probabilistic fault grading method is described. The concept of propagation probability is introduced in place of the sensitization probability of STAFAN, and the empirical parameters of STAFAN are eliminated. The division of input vectors into subsets is monitored by the activation or toggle rate. The accuracy of the method is examined for fault coverage estimation and for predicting the undetected faults. 相似文献
43.
Saito K Hosono K Kitazawa N Iwasaki Y Ito R Nakazawa H 《Journal of AOAC International》2011,94(3):923-930
A quality assessment method for commercially available, optically active flavor compounds, namely, menthol, menthyl acetate, borneol, perillaldehyde, and 1,8-cineol, was developed. A gas chromatograph equipped with a flame ionization detector and a DB-5ms capillary column was used for the chemical purity test. A GC/MS with a beta-DEX cyclodextrin column was used for the optical purity test, by which the enantiomeric separation of each flavor compound was achieved. Enantiomeric excess was calculated as an expression of optical purity. Of the 25 standard samples subjected to the chemical purity test, six were found to have lower purity than the data provided by the manufacturers. When the same samples were subjected to the optical purity test, 11 were found to have lower purity than that indicated on the reagent labels. These results suggest that there is a need to conduct an optical purity test, in addition to a chemical purity test, for the quality assessment of flavor standards. 相似文献
44.
Saito K Kohama J Sakamoto Y Iwasaki Y Ito R Horie M Nakazawa H 《Journal of AOAC International》2011,94(2):482-486
The chiral separation and quantification of D-proline and L-proline in honey and royal jelly were examined by LC with UV detection. Most of the endogenous compounds existing in honey, such as sugars, were removed by using SPE cartridges containing C18 and strong cation-exchange sorbent. Other components, such as primary amino acids, were also removed by two-step derivatization with o-phthalaldehyde (OPA) and 9-fluorenylmethyl chloroformate (FMOC-CI). The components that were derivatized with OPA were separated from proline with a C18 cartridge. Proline was then converted into an FMOC derivative that could be subsequently measured by LC-UV. Sufficient chiral separation of D-proline and L-proline was achieved with an LC chiral column made of a beta-cyclodextrin phase in the polar organic-phase mode. The average recoveries of D-proline and L-proline from honey and royal jelly were in the range of 81.3-98.6% (RSD of < 1.8%). When this method was applied to commercial honey and royal jelly samples, L-proline was detected at concentrations of 369-1930 microg/g, whereas D-proline was not detected. 相似文献
45.
The soliton self-frequency shift (SSFS) in orthogonally polarised femtosecond soliton pulses is reported for the first time. It is shown that SSFS for orthogonally polarised solitons is approximately 1/3 of that for parallel polarised solitons. This is attributed to the orthogonal Raman term. The 2π and π dependences of the SSFS on the phase difference between the two solitons are newly obtained for parallel and orthogonal polarisations, respectively. The largest SSFS occurs in-phase under parallel polarisation 相似文献
46.
47.
M Horie K Saito Y Hoshino N Nose N Hamada H Nakazawa 《Journal of chromatography. A》1990,502(2):371-378
A simple and selective method for the determination of sulphamethazine (SMT) and its metabolite, N4-acetylsulphamethazine (N4-AcSMT), in meat by high-performance liquid chromatography (HPLC) with photodiode-array detection was developed. The drugs were extracted from meat with 0.2% metaphosphoric acid-methanol (6:4), followed by a Bond-Elut C18 clean-up procedure. The HPLC separation was carried out on a Supersphere RP-18e column (125 X 4.0 mm I.D.) using 0.05 M sodium dihydrogenphosphate (pH 4.5)-acetonitrile (8:2) as the mobile phase at a flow-rate of 0.5 ml/min, and monitored with a photodiode-array detector. The recoveries of SMT and N4-AcSMT from meat fortified at 0.5 micrograms/g were 90.1-93.3 and 93.0-94.4%, respectively, with coefficients of variation of 1.9-3.2 and 1.5-2.7%. The limits of detection were 0.02 micrograms/g for each drug. SMT was found in ten samples of imported meat (12.5%) at levels ranging from 0.05 to 1.05 micrograms/g. 相似文献
48.
A 10 Gbit/s pseudorandom (PR) dark soliton data signal has been successfully transmitted over 1200 km for the first time. The dark soliton source was a 1.53 μm DFB LD and was modulated with a push-pull Mach-Zehnder LiNbO3 intensity modulator. A T-flip-flop circuit was used to generate the PR dark soliton. A one-bit-shifting scheme with a Mach-Zehnder interferometer was used to convert the dark soliton train into a conventional NRZ signal 相似文献
49.
T. Komukai K. Tamura M. Nakazawa 《Photonics Technology Letters, IEEE》1997,9(7):934-936
A narrow-band apodized fiber Bragg grating was fabricated with a phase mask method that incorporated a fluorescence monitoring technique. The grating length was 100 mm and the 3-dB reduced bandwidth was as small as 0.04 nm. The 20-dB reduced bandwidth was 0.1 nm at a center wavelength of 1554 mm. A single longitudinal oscillation mode of a 10-GHz pulse train from a mode-locked fiber laser was successfully extracted using the grating. 相似文献
50.
It is shown by computer runs and simple analysis that one hundred million km soliton transmission is possible by means of soliton transmission controls in the time and frequency domains. This means that limitless transmission is possible. The key to success is to reduce noise by the synchronous modulation technique which can also reduce timing jitter and nonlinear interaction forces. The accumulated noise converges to a fixed low level even after limitless transmission.<> 相似文献