全文获取类型
收费全文 | 1563篇 |
免费 | 33篇 |
国内免费 | 7篇 |
专业分类
化学 | 1112篇 |
晶体学 | 6篇 |
力学 | 13篇 |
数学 | 258篇 |
物理学 | 214篇 |
出版年
2020年 | 16篇 |
2019年 | 15篇 |
2017年 | 11篇 |
2016年 | 23篇 |
2015年 | 30篇 |
2014年 | 32篇 |
2013年 | 62篇 |
2012年 | 27篇 |
2011年 | 39篇 |
2010年 | 37篇 |
2009年 | 38篇 |
2008年 | 76篇 |
2007年 | 53篇 |
2006年 | 68篇 |
2005年 | 55篇 |
2004年 | 46篇 |
2003年 | 58篇 |
2002年 | 54篇 |
2001年 | 40篇 |
2000年 | 31篇 |
1999年 | 32篇 |
1998年 | 28篇 |
1997年 | 25篇 |
1996年 | 29篇 |
1995年 | 27篇 |
1994年 | 45篇 |
1993年 | 38篇 |
1992年 | 52篇 |
1991年 | 22篇 |
1990年 | 15篇 |
1989年 | 18篇 |
1988年 | 23篇 |
1987年 | 32篇 |
1986年 | 24篇 |
1985年 | 23篇 |
1984年 | 23篇 |
1983年 | 28篇 |
1982年 | 21篇 |
1981年 | 16篇 |
1980年 | 21篇 |
1979年 | 21篇 |
1978年 | 28篇 |
1977年 | 18篇 |
1976年 | 13篇 |
1975年 | 17篇 |
1974年 | 26篇 |
1973年 | 20篇 |
1972年 | 16篇 |
1971年 | 21篇 |
1970年 | 12篇 |
排序方式: 共有1603条查询结果,搜索用时 0 毫秒
11.
The tunneling of single electrons in small capacitance tunnel junctions is influenced by charging effects and by the fluctuations of the elecromagnetic environment. We study the effect of an external circuit with arbitrary impedance on the tunneling of quasiparticles and Cooper pairs in voltage driven Josephson junctions. We present results at finite temperatures and also consider an acdriven system. 相似文献
12.
Gerd Herzog Christoph Schmoeger 《Proceedings of the American Mathematical Society》2003,131(11):3507-3509
We prove the converse of Raubenheimer and Rode's Banach algebra version of the Perron-Frobenius Theorem.
13.
The purpose of this pilot study was to establish the dependence or independence of oxalate absorption on the quantity of the test dose of sodium oxalate over a range of test doses corresponding to physiological dietary oxalate intake values. Gastrointestinal oxalate absorption was measured with the [13C2]oxalate absorption test. Six healthy volunteers were always tested under standardized dietary conditions with 63 mg dietary oxalate and 800 mg dietary calcium per day. The volunteers were tested thrice each with sodium oxalate test doses of 25, 50, 200, and 600 mg. Additionally, 1000 mg sodium oxalate was applied once to three of these volunteers. The oxalate absorption of the six volunteers tested under the standardized conditions with 50 mg sodium [13C2]oxalate was 7.2 +/- 2.62 % (mean +/- SD), similar to the 120 volunteers tested previously: 8.0 +/- 4.4 % (mean +/- SD). The tests with sodium [13C2]oxalate doses in the range 25-1000 mg revealed similar percent oxalate absorption values. In conclusion, in healthy volunteers, the amount of oxalate absorbed in the gastrointestinal tract increased proportionally with the higher test doses of oxalate. However, percent oxalate absorption remained unchanged with test doses in the dose range of physiological dietary oxalate intakes. 相似文献
14.
We evaluate the current distribution for a single-electron transistor with intermediate strength tunnel conductance. Using the Schwinger-Keldysh approach and the drone (Majorana) fermion representation, we account for the renormalization of system parameters. Nonequilibrium effects induce a lifetime broadening of the charge-state levels, which suppress large current fluctuations. 相似文献
15.
16.
Following Mie theory, nanoparticles made of a high‐refractive‐index dielectric, such as silicon, exhibit a resonator‐like behavior and very rich resonance spectra. Which electric or magnetic particle mode is excited depends on the wavelength, the refractive‐index contrast relative to the environment, and the geometry of the nanoparticle itself. In addition, the spatial structure of the impinging light field plays a major role in the excitation of the nanoparticle resonances. Here, it is shown that, by tailoring the excitation field, individual multipole resonances can be selectively addressed while suppressing the excitation of other particle modes. This enables a detailed study of selected individual resonances without interference by the other modes.
17.
Ritesh Sachan Abhinav Malasi Sagar Yadavali Blake Griffey John Dunlap Gerd Duscher Ramki Kalyanaraman 《Particle & Particle Systems Characterization》2015,32(4):476-482
Currently, one of the challenges in high‐resolution transmission electron microscopy (TEM) studies of nanomaterials is to make contamination‐free materials in a simple and time‐efficient way. Here, a method is demonstrated that combines nanosecond‐pulsed laser dewetting of thin films with a film float‐off technique to realize nanostructures (NSs) on electron‐transparent substrates in a robust and rapid manner. NSs of metal (Ag) and bimetals (AgCo, AuCo) ranging from 20 to 150 nm are synthesized on thin carbon film deposited on mica substrates. The NS/carbon system is subsequently transferred onto TEM grids by a float‐off process resulting from debonding of the carbon from mica due to their contrasting hydrophobic nature. This process enables the fabrication of different NSs on flexible and electron‐transparent substrates. 相似文献
18.
19.
Gerd Bergmann 《Zeitschrift für Physik B Condensed Matter》1997,102(3):381-383
It is numerically shown that the groundstate of the Friedel problem (consisting of a conduction band and a dresonance), occupied with (n+ 1) electrons, can be written as Ψ = (A a 0 * +Bd*) Π v=1 n a v * Φ0, where a 0 * represents a localized conduction electron state, d* is the Friedel resonance state and Π v=1 n a v 8 Φ0 is a Slater determinant of n single electron states a t * , (Φ0 is the vacuum state). The a i * together with a 0 * are part of a full ortho-normalized basis of the conductions band. 相似文献
20.