全文获取类型
收费全文 | 52813篇 |
免费 | 6792篇 |
国内免费 | 5223篇 |
专业分类
化学 | 22805篇 |
晶体学 | 401篇 |
力学 | 2455篇 |
综合类 | 324篇 |
数学 | 4221篇 |
物理学 | 14126篇 |
综合类 | 20496篇 |
出版年
2024年 | 209篇 |
2023年 | 872篇 |
2022年 | 1564篇 |
2021年 | 1592篇 |
2020年 | 1587篇 |
2019年 | 1395篇 |
2018年 | 1372篇 |
2017年 | 1332篇 |
2016年 | 1886篇 |
2015年 | 2128篇 |
2014年 | 2625篇 |
2013年 | 3300篇 |
2012年 | 3722篇 |
2011年 | 3876篇 |
2010年 | 2917篇 |
2009年 | 2949篇 |
2008年 | 3317篇 |
2007年 | 3046篇 |
2006年 | 2766篇 |
2005年 | 2438篇 |
2004年 | 1867篇 |
2003年 | 1549篇 |
2002年 | 1476篇 |
2001年 | 1330篇 |
2000年 | 1199篇 |
1999年 | 1636篇 |
1998年 | 1327篇 |
1997年 | 1405篇 |
1996年 | 1272篇 |
1995年 | 1144篇 |
1994年 | 963篇 |
1993年 | 862篇 |
1992年 | 748篇 |
1991年 | 666篇 |
1990年 | 627篇 |
1989年 | 531篇 |
1988年 | 423篇 |
1987年 | 327篇 |
1986年 | 204篇 |
1985年 | 139篇 |
1984年 | 70篇 |
1983年 | 54篇 |
1982年 | 55篇 |
1981年 | 23篇 |
1980年 | 14篇 |
1979年 | 6篇 |
1959年 | 1篇 |
1957年 | 9篇 |
1955年 | 3篇 |
1936年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
Jie Xue Liang Chen Li Zhou Zhifeng Jia Yanping Wang Xinyuan Zhu Deyue Yan 《Journal of Polymer Science.Polymer Physics》2006,44(15):2050-2057
α‐Cyclodextrin (α‐CD) has been complexed with various poly(ethylene glycol) (PEG) derivatives in aqueous solution. It has been found that the end groups of PEG derivatives affect the complexation kinetics greatly, but have only a little influence on the thermodynamic behavior. By increasing the hydrophobicity of end groups, the complexation speeds up rapidly. On the other hand, the bulky end groups slow down the threading of polymeric guests into the cavity of CD. By changing the hydrophobicity and the size of end groups, the complexation rate can be adjusted in the range of several orders of magnitudes, which should be quite useful in the design of new supramolecular systems. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2050–2057, 2006 相似文献
143.
The glutathione (GSH) monolayer and complex monolayer of GSH-metallic ion on polycrystalline gold electrode were studied by
using K3Fe(CN)6 as the redox probe. As for the GSH monolayer, it was found that the metallic ions could open the ion-gate in the monolayer
dramatically in the order La3+> Pb2+>>Ba2+>Ca2+ whereas Zn2+ ion closed the ion-gate. The complexes of GSH-metallic ions were capable of self-assembling the different kind of monolayer.
All the differences were related to the structural configuration of the anchored GSH molecule, which changed with different
metallic ions or pH.
Biography:Fang Cheng (1971-) male, Ph. D, research direction: electroanlysis. 相似文献
144.
145.
Laser driven shocks can lead to a dynamic failure, called film spallation. Here, we use a modified laser spallation set-up
to measure the dynamic adhesion of thin films and we propose a novel diagnostic technology. Based on correlation theory, new
spallation criteria for characterizing the progressive damage at the interface between the film and the substrate are established,
such as interface delamination, film spallation and film expulsion. With the help of the theory, the degree of damage and
the dimension of damage (i.e. fracture), such as the minimum width of delamination radius, the thickness of the film etc.,
are estimated. Experiments are carried out on epoxy/stainless steel and epoxy/Al, and the experimental results show that their
dynamic bonding strengths are about 25 MPa and 20 MPa, respectively. The detailed results, analyses and discussions are presented
in this paper.
Received: 6 February 2001 / Accepted: 3 December 2001 / Published online: 11 February 2002 相似文献
146.
147.
Ying Zhang Gang Hu Shigang Chen H.A. Cerdeira 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(3):381-384
A method of controlling global stochasticity in Hamiltonian systems by applying nonlinear perturbation is proposed. With the
well-known standard map we demonstrate that this control method can convert global stochasticity into regular motion in a
wide chaotic region for arbitrary initial condition, in which the control signal remains very weak after a few kicks. The
system in which chaos has been controlled approximates to the original Hamiltonian system, and this approach appears robust
against small external noise. The mechanism underlying this high control efficiency is intuitively explained.
Received 15 January 2002 Published online 6 June 2002 相似文献
148.
Catherine Cordier-Robert Thierry Grosdidier Gang Ji Jacques Foct 《Hyperfine Interactions》2006,168(1-3):951-957
Microstructured (atomized) and nanostructured (milled) Fe60Al40 powders together with their corresponding coatings synthesized by High Velocity Oxy-fuel (HVOF) or Atmospheric Plasma Spray (APS) thermal spraying techniques have been characterized by Mössbauer Spectroscopy (MS) and X-ray Diffraction (XRD). The evolution of the microstructure and the atomic ordering degree in the powders and coatings are discussed at the light of the various processing conditions. The operational correlation between the parameters of the duplex morphology of coatings and the processing parameters is discussed. 相似文献
149.
X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic recombination, collisional ionization and resonance excitation from the neighbouring ion (Al^9+ and Al^11+ ) charge states of the target ion (Al^10+) are considered in the model. In addition, the contributions of different atomic processes to the x-ray spectrum are analysed. The results show that dielectronic recombination, radiative recombination, collisional ionization and resonance excitation, other than direct collisional excitation, are very important processes. 相似文献
150.