全文获取类型
收费全文 | 187篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
化学 | 68篇 |
晶体学 | 3篇 |
力学 | 8篇 |
数学 | 5篇 |
物理学 | 55篇 |
无线电 | 55篇 |
出版年
2023年 | 6篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 12篇 |
2012年 | 13篇 |
2011年 | 16篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1984年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1943年 | 1篇 |
1930年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有194条查询结果,搜索用时 15 毫秒
11.
12.
Kobrinsky M.J. Chakravarty S. Jiao D. Harmes M.C. List S. Mazumder M. 《Advanced Packaging, IEEE Transactions on》2005,28(1):57-62
Since the design of advanced microprocessors is based on simulation tools, accurate assessments of the amount of crosstalk noise are of paramount importance to avoid logic failures and less-than-optimal designs. With increasing clock frequencies, inductive effects become more important, and the validity of assumptions commonly used in simulation tools and approaches is unclear. We compared accurate experimental S-parameters with results derived from both magneto-quasi-static and full-wave simulation tools for simple crosstalk structures with various capacitive and inductive couplings, in the presence of parallel and orthogonal conductors. Our validation approach made possible the identification of the strengths and weaknesses of both tools as a function of frequency, which provides useful guidance to designers who have to balance the tradeoffs between accuracy and computation expenses for a large variety of cases 相似文献
13.
An optimal resource utilization framework to analyze the impact of end-to-end delay thresholds on the wireless network throughput is developed. In contrast to conventional networks where lumped transmission and queuing delays are used to model the end-to-end delay, the proposed framework models these delay components separately to analyze their relative contribution to the end-to-end delay when stringent delay thresholds are used. A 'log' utility maximization problem is formulated and its distributed implementation using dual decomposition is proposed. Our optimization results show that decreasing the delay threshold leads to larger contribution from the transmission delay to the end-to-end delay. 相似文献
14.
A set of coupled differential equations obtained by Wanas in the Mikhail-Wanas generalized field theory is completely integrated. 相似文献
15.
Gonzalez A.F. Bhattacharya M. Kulkarni S. Mazumder P. 《Solid-State Circuits, IEEE Journal of》2001,36(6):924-932
This paper presents a fully integrated implementation of a multivalued-logic signed-digit full adder (SDFA) circuit using a standard 0.6-μm CMOS process. The radix-2 SDFA circuit, based on two-peak negative-differentiaI-resistance (NDR) devices, has been implemented using MOS-NDR, a new prototyping technique for circuits that combine MOS transistors and NDR devices. In MOS-NDR, the folded current-voltage characteristics of NDR devices such as resonant-tunneling diodes (RTDs) are emulated using only nMOS transistors. The SDFA prototype has been fabricated and correct function has been verified. With an area of 123.75 by 38.7 μm2 and a simulated propagation delay of 17 ns, the MOS-NDR prototype is more than 15 times smaller and slightly faster than the equivalent hybrid RTD-CMOS implementation 相似文献
16.
NirmlaDevi Thakur Vilas G. Gaikar Debasis Sen Subhasish Mazumder Nancy S. Pandita 《Analytical letters》2017,50(4):690-711
A green method using Juglans regia bark extract was used to synthesize silver nanoparticles at room temperature with monitoring by absorption spectroscopy. The size and shape of the synthesized nanoparticles were characterized by infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and small-angle X-ray scattering. The average particle size was from 10 to 30?nm. Gas chromatography–mass spectrometry (GC–MS) was used for the separation, identification, and quantification of components of the plant extracts. A possible mechanism for the synthesis of nanoparticles was elucidated based on the GC–MS results. The synthesized silver nanoparticles showed effective inhibition against Streptococcus mutans, which is the main causative agent for dental caries. The nanoparticles also showed promising antibiofilm activity by inhibiting the glucosyltransferase enzyme. 相似文献
17.
Nairwita Mazumder Ritabrata Biswas Subenoy Chakraborty 《General Relativity and Gravitation》2011,43(6):1827-1836
Here we consider our universe as inhomogeneous spherically symmetric Lema
[^(i)]{\hat{i}}
tre−Tolman−Bondi Model and analyze the thermodynamics of this model of the universe. The trapping horizon is calculated and is found to coincide
with the apparent horizon. The Einstein field equations are shown to be equivalent with the unified first law of thermodynamics.
Finally assuming the first law of thermodynamics validity of the generalized second law of thermodynamics is examined at the
apparent horizon for the perfect fluid and at the event horizon for holographic dark energy. 相似文献
18.
Nairwita Mazumder Subenoy Chakraborty 《International Journal of Theoretical Physics》2011,50(1):251-259
In this paper, we investigate the validity of the generalized second law of thermodynamics of the universe bounded by the
event horizon. Here we consider homogeneous and isotropic model of the universe filled with perfect fluid in one case and
in another case holographic model of the universe has been considered. In the third case the matter in the universe is taken
in the form of non-interacting two fluid system as holographic dark energy and dust. Here we study the above cases in the
Modified gravity, f(R) gravity. 相似文献
19.
Suiyuan Chen Jing LiangChangsheng Liu Kai SunJyoti Mazumder 《Applied Surface Science》2011,258(4):1443-1450
A high wear-resistant gradient coating made of Ni/Co-based alloys on the surface of a Cu alloy substrate was synthesized using a YAG laser induced in situ reaction method. The coating consists of three layers: the first is a Ni-based alloy layer, the second and third are Co-based alloy layers. The microhardness increases gradually from 98 HV in the Cu alloy substrate to the highest level of 876 HV in the third layer. The main phase of the Co-based alloy layer is CoCr2(Ni,O)4, coexisting with the Fe13Mo2B5, Cr(Co(Mo, and FeCr0.29Ni0.16C0.06 phases. Wear tests indicate that the gradient coating has good bond strength and wear properties with a wear coefficient of 0.31 (0.50 for the Cu alloy substrate). Also, the wear loss of the coating is only 0.01 g after it has been abraded for 60 min, which is only one fifth of that of the Cu alloy of the crystallizer. Wear tests of the gradient coating reveal good adhesive friction and wear properties when sliding against steel under dry conditions. This novel technique may have good application to make an advanced coating on the surface of the Cu alloy crystallizer in a continuous casting process. 相似文献
20.
Direct metal deposition (DMD) with coaxial powder injection allows fabrication of three-dimensional geometry with rapidly solidified microstructure. During DMD, addition of powder leads to the interaction between laser and powder, and also the redistribution of solute. The concentration distribution of the alloying element is very important for mechanical properties of the deposited clad material. The evolution of concentration distribution of carbon and chromium in the molten pool is simulated using a self-consistent three-dimensional model, based on the solution of the equations of mass, momentum, energy conservation and solute transport in the molten pool. The experimental and calculated molten pool geometry is compared for model validation purposes. 相似文献