全文获取类型
收费全文 | 1224篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
化学 | 713篇 |
晶体学 | 12篇 |
力学 | 12篇 |
数学 | 66篇 |
物理学 | 290篇 |
无线电 | 152篇 |
出版年
2019年 | 12篇 |
2018年 | 11篇 |
2016年 | 10篇 |
2015年 | 15篇 |
2014年 | 17篇 |
2013年 | 43篇 |
2012年 | 43篇 |
2011年 | 41篇 |
2010年 | 32篇 |
2009年 | 29篇 |
2008年 | 42篇 |
2007年 | 49篇 |
2006年 | 36篇 |
2005年 | 52篇 |
2004年 | 40篇 |
2003年 | 42篇 |
2002年 | 43篇 |
2001年 | 24篇 |
2000年 | 23篇 |
1999年 | 24篇 |
1998年 | 25篇 |
1997年 | 21篇 |
1996年 | 21篇 |
1995年 | 18篇 |
1994年 | 26篇 |
1993年 | 19篇 |
1992年 | 32篇 |
1991年 | 15篇 |
1990年 | 16篇 |
1989年 | 18篇 |
1988年 | 21篇 |
1987年 | 15篇 |
1986年 | 20篇 |
1985年 | 17篇 |
1984年 | 27篇 |
1983年 | 16篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 15篇 |
1979年 | 23篇 |
1978年 | 8篇 |
1977年 | 17篇 |
1976年 | 18篇 |
1975年 | 23篇 |
1974年 | 20篇 |
1973年 | 17篇 |
1972年 | 19篇 |
1971年 | 10篇 |
1966年 | 10篇 |
1965年 | 12篇 |
排序方式: 共有1245条查询结果,搜索用时 0 毫秒
1.
Takauchi H. Tamura H. Matsubara S. Kibune M. Doi Y. Chiba T. Anbutsu H. Yamaguchi H. Mori T. Takatsu M. Gotoh K. Sakai T. Yamamura T. 《Solid-State Circuits, IEEE Journal of》2003,38(12):2094-2100
We describe a CMOS multichannel transceiver that transmits and receives 10 Gb/s per channel over balanced copper media. The transceiver consists of two identical 10-Gb/s modules. Each module operates off a single 1.2-V supply and has a single 5-GHz phase-locked loop to supply a reference clock to two transmitter (Tx) channels and two receiver (Rx) channels. To track the input-signal phase, the Rx channel has a clock recovery unit (CRU), which uses a phase-interpolator-based timing generator and digital loop filter. The CRU can adjust the recovered clock phase with a resolution of 1.56 ps. Two sets of two-channel transceiver units were fabricated in 0.11-/spl mu/m CMOS on a single test chip. The transceiver unit size was 1.6 mm /spl times/ 2.6 mm. The Rx sensitivity was 120-mVp-p differential with a 70-ps phase margin for a common-mode voltage ranging from 0.6 to 1.0 V. The evaluated jitter tolerance curve met the OC-192 specification. 相似文献
2.
3.
Haus H.A. Khatri F.I. Wong W.S. Ippen E.P. Tamura K.R. 《Quantum Electronics, IEEE Journal of》1996,32(6):917-924
The interaction of a soliton of the Nonlinear Schrodinger Equation (NSE) with a weak sinusoidal wave packet is treated analytically. The second-order soliton solution containing the original soliton and a perturbing soliton is expanded to first order in the amplitude of the perturbating soliton. From this expansion, one obtains the associate function of Gordon (1992) and a continuous change of position and phase of the perturbed soliton. One finds that the soliton experiences a second-order change of velocity under the influence of the perturbation. This result is then used to derive the displacement due to a wave packet of general shape, which is also confirmed by computer simulation 相似文献
4.
Michiko Tamura 《Geometriae Dedicata》1992,42(3):311-315
LetM be a complete smooth surface of constant mean curvature in the Euclidean 3-space. If there exists two helical geodesics onM through each point ofM, thenM is either a plane, a sphere, or a circular cylinder. 相似文献
5.
A relativistic Green function formalism has been applied to calculate layer-projected densities of states on Pd(110). In particular, we obtained unoccupied surface states and their dispersion relations along two directions in the surface Brillouin zone. Good agreement with recent inverse photoemission data is reached by using an energy-dependent dynamical surface potential barrier, which is based on a simple electron-plasmon interaction model, instead of a static surface barrier. 相似文献
6.
Tadao Seguchi Naoyuki Tamura 《Journal of polymer science. Part A, Polymer chemistry》1974,12(9):1953-1964
The regions trapping allyl radicals in irradiated polyethylene and the reactivity of the radicals with various monomers have been studied by electron spin resonance. Most of the allyl radicals are trapped in defects or surfaces of the crystallite, and only 10% of the radicals are trapped inside the crystallites. Since the reactivity of the allyl radicals depends on whether they come in contact with reactive monomers, the rate of reaction is related to the concentration of the monomers. When grafting reactions are initiated by allyl radicals, the rate of initiation is rapid and the rate of termination at the initial stage is also very fast. Consequently the yield of grafting increases at the initial stage but soon levels off, which is in contrast to the grafting behavior with alkyl radicals. 相似文献
7.
An interesting transformation occurs during acylation of 4(R)-hydroxymethyl-3-methyl-1,3-thiazolidine when 4(R)-acylthiomethyl-3-methyl-1,3-oxazolidines are yielded: the reaction competing with O-acylation is controlled by the bulkiness of the acyl group. 相似文献
8.
Y. Sakaiguchi T. Shikata H. Urakami A. Tamura H. Hirata 《Colloid and polymer science》1987,265(8):750-753
Some cationic surfactants such as cetyltrimethylammonium bromide (CTAB) show a very spectacular viscoelasticity in solution, in even very diluted states, with some aromatic substances added, such as salicylic acid. Formerly, the authors established that the remarkable solution behaviour was the result of the entanglement of such enormously elongated giant micelles, based on recognition of the existence of large aggregates, through direct observation of them as substantial images under the electron microscope.In this report, we further confirm the relation between micelle length and solution viscoelasticity after arbitrarily obtaining different size aggregates by altering the media pH, or by admixing shorter chain length surfactants than CTAB, which alone did not induce viscoelasticity. 相似文献
9.
10.