全文获取类型
收费全文 | 13285篇 |
免费 | 1621篇 |
国内免费 | 2412篇 |
专业分类
化学 | 10914篇 |
晶体学 | 70篇 |
力学 | 530篇 |
综合类 | 117篇 |
数学 | 1182篇 |
物理学 | 4505篇 |
出版年
2024年 | 15篇 |
2023年 | 158篇 |
2022年 | 295篇 |
2021年 | 367篇 |
2020年 | 420篇 |
2019年 | 397篇 |
2018年 | 312篇 |
2017年 | 382篇 |
2016年 | 443篇 |
2015年 | 449篇 |
2014年 | 576篇 |
2013年 | 902篇 |
2012年 | 1100篇 |
2011年 | 756篇 |
2010年 | 647篇 |
2009年 | 821篇 |
2008年 | 914篇 |
2007年 | 999篇 |
2006年 | 961篇 |
2005年 | 834篇 |
2004年 | 821篇 |
2003年 | 671篇 |
2002年 | 527篇 |
2001年 | 416篇 |
2000年 | 405篇 |
1999年 | 356篇 |
1998年 | 331篇 |
1997年 | 324篇 |
1996年 | 213篇 |
1995年 | 213篇 |
1994年 | 200篇 |
1993年 | 190篇 |
1992年 | 176篇 |
1991年 | 153篇 |
1990年 | 132篇 |
1989年 | 85篇 |
1988年 | 66篇 |
1987年 | 42篇 |
1986年 | 39篇 |
1985年 | 34篇 |
1984年 | 19篇 |
1983年 | 13篇 |
1982年 | 34篇 |
1981年 | 25篇 |
1980年 | 20篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
EQCM and voltammetric data show that thallium(I) ions, which are adsorbed in the region of the positive surface charge, most probably, in the form of the ionic pairs, are not reduced. In this potential region, thallium(I) ions are reduced directly from the solution. At more negative potentials, the previously adsorbed stable ionic pairs slowly undergo transition into the less stable form. From this form, thallium(I) ions can be reduced or desorbed into the solution. The process is best described by a model of one electron, i.e., full charge transfer. 相似文献
12.
Gui Hong YAN Da XING* Shi Ci TAN Institute of Laser Life Science South China Normal University Guangzhou 《中国化学快报》2004,15(1):101-104
Electrochemiluminescence (ECL), like other chemiluminescence technique, offers high signal-to-noise ratio. Furthermore, it has the advantage over other chemiluminescence techniques of being initiated by a voltage potential. Thus, it provides a better-controlled luminescence. This technique has been used in measuring many kinds of organic and inorganic matters, and analyzing many kinds of antigen, antibody and hapten, such as carcinoembryonic antigen and alpha-fetoprotein, etc1-6. The ele… 相似文献
13.
L. A. Sakhnovich 《Functional Analysis and Its Applications》2002,36(3):205-211
The conjecture according to which the mean energy of an equilibrium system in quantum theory exceeds the mean energy of the corresponding classical system is considered. It is rigorously proved that the conjecture holds for the potential well. The estimates for the mean energy of the potential well at high and low temperatures are of special interest. 相似文献
14.
15.
Maxim Perelstein 《Pramana》2006,67(5):813-820
Little Higgs models are an interesting extension of the Standard Model at the TeV scale. They provide a simple and attractive
mechanism of electroweak symmetry breaking. We review one of the simplest models of this class, the Littlest Higgs model,
and its extension with T parity. The model with T parity satisfies precision electroweak constraints without fine-tuning, contains an attractive dark matter candidate, and
leads to interesting phenomenology at the Large Hadron Collider (LHC). 相似文献
16.
One influential parameter which mediates interactions between many types of molecules and biological membranes stems from
the lumped contributions of the transmembrane potential, dipole potential and the difference in the surface potentials on
both sides of a membrane. With relevance to cell physiology, such electrical features of a biomembrane are prone to undergoing
changes as a result of interactions with the aqueous surrounding. Among the most useful tools devoted to exploring changes
of electrical parameters of a lipid membrane induced by certain extracellular ions, lipid composition, and embedded membrane
peptides and proteins, are spectroscopic imaging and the inner field compensation (IFC) method. In this work we layout the
principles of a fully computerized version of the IFC method, which makes it more readily available to users. As a direct
application, we deployed this improved version of the IFC method to time-resolve changes induced by alamethicin monomers upon
membrane dipole potential, following their aggregation within an artificial lipid membrane. Intriguingly, even prior crossing
the membrane core, the membrane-bound alamethicin monomers are shown to significantly increase the dipole potential of the
monolayer they reside in. Such data further emphasize the yet less-explored interplay between membrane-based protein and peptides,
and the membrane dipole potential. 相似文献
17.
The refractive indices (n) of eight standard oils from Physikalisch Technische Bundesanstalt, Germany were determined with an accuracy of ±1×10−4 by using Abbe Refractometer. The measurements were performed at temperature 20°C in the spectral range 0.4–0.7 μm. The experimental data were fitted to the simple Cauchy dispersion formula and the results were found to be consistent within the limits of experimental error. In all cases, the refractive index decreased monotonically with increasing wavelength. The refractive indices (n) of these oils have been measured as a function of the temperature t (20°C up to 50°C) at λ=0.589 μm and were found to have linear temperature dependencies. The refractive indices of the studied oils and the uncertainty in their values are calculated at λ=0.589. The Lorentz–Lorenz (L–L) formula has been tested and it was found to be valid with a maximum deviation of 0.4% and was used to calculate the molecular polarizability θ. 相似文献
18.
The kinetics of reactions occurring at the gas-exposed surfaces of charged mixed ionic electronic conductors (MIECs) are examined
from theoretical first principles. Analysis based on the classical electrochemical potential-transition state theory model
reveals that the nature of the reactions is electrochemical in general. However, the influence of the surface potential on
the reaction rate is opposite for adsorption and incorporation reactions. Two-dimensional finite volume models of an MIEC
as working electrode in a half-cell configuration are presented. The results for a simple, two-step reduction process show
that the effect of the surface potential on the rate of reactions is minimal for incorporation-limited reactions but more
influential for adsorption-limited reactions.
An erratum to this article is available at . 相似文献
19.
Maria Mamalui Chien-Yueh Huang 《Physica E: Low-dimensional Systems and Nanostructures》2004,22(4):912-920
We present the theoretical study of the effect of external random field characterized by a Gaussian probability distribution function on the continuous phonon spectrum of one-dimensional (1D) chain, based on the Jacobian matrix method. The cumulative effect of the random field and simple isotopic defect is studied analytically and numerically. The Gaussian random field removes a square-root divergence appearing in the phonon spectrum of ideal 1D chain. The impurity phonon DOS shows strong dependence on the variance and the mean of the random field and exhibits very different behavior from the non-random case: the continuous spectrum is expanded and the δ-peak, describing discrete impurity vibrations in the non-random chain with the impurity, falls into a continuous zone. 相似文献
20.
Letters in Mathematical Physics - 相似文献