全文获取类型
收费全文 | 9542篇 |
免费 | 388篇 |
国内免费 | 19篇 |
专业分类
化学 | 6170篇 |
晶体学 | 68篇 |
力学 | 344篇 |
数学 | 1382篇 |
物理学 | 1481篇 |
无线电 | 504篇 |
出版年
2023年 | 58篇 |
2022年 | 80篇 |
2021年 | 134篇 |
2020年 | 164篇 |
2019年 | 172篇 |
2018年 | 193篇 |
2017年 | 168篇 |
2016年 | 330篇 |
2015年 | 261篇 |
2014年 | 297篇 |
2013年 | 608篇 |
2012年 | 595篇 |
2011年 | 683篇 |
2010年 | 374篇 |
2009年 | 350篇 |
2008年 | 600篇 |
2007年 | 629篇 |
2006年 | 559篇 |
2005年 | 542篇 |
2004年 | 417篇 |
2003年 | 392篇 |
2002年 | 307篇 |
2001年 | 148篇 |
2000年 | 137篇 |
1999年 | 126篇 |
1998年 | 96篇 |
1997年 | 85篇 |
1996年 | 121篇 |
1995年 | 101篇 |
1994年 | 87篇 |
1993年 | 81篇 |
1992年 | 71篇 |
1991年 | 58篇 |
1990年 | 47篇 |
1989年 | 49篇 |
1988年 | 34篇 |
1987年 | 34篇 |
1985年 | 64篇 |
1984年 | 47篇 |
1983年 | 41篇 |
1982年 | 55篇 |
1981年 | 45篇 |
1980年 | 56篇 |
1979年 | 45篇 |
1978年 | 41篇 |
1977年 | 38篇 |
1976年 | 49篇 |
1975年 | 48篇 |
1974年 | 33篇 |
1973年 | 31篇 |
排序方式: 共有9949条查询结果,搜索用时 15 毫秒
921.
922.
923.
In a probabilistic model of a film over a disordered substrate, Monte-Carlo simulations show that the film hangs from peaks of the substrate. The film profile is well approximated by a necklace of Wulff shapes. Such a necklace can be obtained as the infimum of a collection of Wulff shapes resting on the substrate. When the random substrate is given by iid heights with exponential distribution, we prove estimates on the probability density of the resulting peaks, at small density.AMS subject classification: 60K35, 60K37, 82B24, 82B41 相似文献
924.
925.
A. T. Fiory S. G. Chawda S. Madishetty V. R. Mehta N. M. Ravindra S. P. Mccoy M. E. Lefrançois K. K. Bourdelle J. M. Mckinley H. -J. L. Gossmann A. Agarwal 《Journal of Electronic Materials》2002,31(10):999-1003
Shallow junctions are formed in crystalline Si by low-energy ion implantation of B+, P+, or As+ species accompanied by electrical activation of dopants by rapid thermal annealing and the special case of spike annealing.
Diffusion depths were determined by secondary ion-mass spectroscopy (SIMS). Electrical activation was characterized by sheet
resistance, Hall coefficient, and reverse-bias diode-leakage measurements. The B+ and P+ species exhibit transient-enhanced diffusion (TED) caused by transient excess populations of Si interstitials. The electrically
activated fraction of implanted dopants depends mainly on the temperature for B+ species, while for P+ species, it depends on both temperature and P+ dose. The relatively small amount of diffusion associated with As+ implants is favorable for shallow-junction formation with spike annealing. 相似文献
926.
This article describes a general kinetic formalism for treating the details of heterogeneous reactions at a gas-solid interface. We develop a nomenclature for treating reactions between the gas phase and surface species residing on any number of surface site types and bulk-phase species residing in bulk-phase mixtures or in pure bulk phases. The rate of progress of surface reactions follows the law of mass-action. We discuss the relationship between macroscopic conservation laws for mass and energy and the microscopic surface reaction rates as they might appear in boundary conditions for a chemically reacting flow. The formalism developed has been implemented in a general package of Fortran computer codes for the evaluation of complex surface-reaction kinetics called Surface Chemkin. 相似文献
927.
928.
Jean-François Lafont 《Journal of Pure and Applied Algebra》2007,209(3):771-780
In this paper, we show that a class of 2-dimensional locally CAT(-1) spaces is topologically rigid: isomorphism of the fundamental groups is equivalent to the spaces being homeomorphic. An immediate application of this result is a diagram rigidity theorem for certain amalgamations of free groups. The direct limits of two such amalgamations are isomorphic if and only if there is an isomorphism between the respective diagrams. 相似文献
929.
Ö. Söğüt E. Baydaş E. Büyükkasap A. Küçükönder Y. Şahin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):13-16
K shell X-ray production cross-sections in the Ti, V, Cr, Mn, Fe, Co, Ni, and Cu in the molecules were studied at 59.5 keV
excitation energy by using a Si(Li) detector ( FWHM = 155 eV at 5.96 keV). The present results are compared with other theoretical values. 相似文献
930.