全文获取类型
收费全文 | 11999篇 |
免费 | 1777篇 |
国内免费 | 1584篇 |
专业分类
化学 | 9076篇 |
晶体学 | 78篇 |
力学 | 738篇 |
综合类 | 121篇 |
数学 | 1418篇 |
物理学 | 3929篇 |
出版年
2024年 | 22篇 |
2023年 | 199篇 |
2022年 | 346篇 |
2021年 | 391篇 |
2020年 | 442篇 |
2019年 | 437篇 |
2018年 | 341篇 |
2017年 | 320篇 |
2016年 | 526篇 |
2015年 | 550篇 |
2014年 | 633篇 |
2013年 | 849篇 |
2012年 | 954篇 |
2011年 | 1018篇 |
2010年 | 745篇 |
2009年 | 697篇 |
2008年 | 758篇 |
2007年 | 670篇 |
2006年 | 672篇 |
2005年 | 607篇 |
2004年 | 469篇 |
2003年 | 437篇 |
2002年 | 547篇 |
2001年 | 466篇 |
2000年 | 303篇 |
1999年 | 274篇 |
1998年 | 235篇 |
1997年 | 181篇 |
1996年 | 185篇 |
1995年 | 187篇 |
1994年 | 159篇 |
1993年 | 114篇 |
1992年 | 90篇 |
1991年 | 126篇 |
1990年 | 83篇 |
1989年 | 75篇 |
1988年 | 63篇 |
1987年 | 47篇 |
1986年 | 34篇 |
1985年 | 29篇 |
1984年 | 20篇 |
1983年 | 12篇 |
1982年 | 16篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1977年 | 3篇 |
1972年 | 2篇 |
1966年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
Pei?WangEmail author Shu?Chen Gao?Xianlong 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(7):164
We study the transport through the Kitaev chain with incommensurate potentials coupled to two normal leads by the numerical operator method. We find a quantized linear conductance of e 2 / h, which is independent to the disorder strength and the gate voltage in a wide range, signaling the Majorana bound states. While the incommensurate potential suppresses the current at finite voltage bias, and then narrows the linear response regime of the I-V curve which exhibits two plateaus corresponding to the superconducting gap and the band edge, respectively. The linear conductance abruptly drops to zero as the disorder strength reaches the critical value 2g s + 2Δ with Δ the p-wave pairing amplitude and g s the hopping between neighbor sites, corresponding to the transition from the topological superconducting phase to the Anderson localized phase. Changing the gate voltage also causes an abrupt drop of the linear conductance by driving the chain into the topologically trivial superconducting phase, whose I-V curve exhibits an exponential shape. 相似文献
152.
Hong‐Hua Fang Jie Yang Jing Feng Takeshi Yamao Shu Hotta Hong‐Bo Sun 《Laser \u0026amp; Photonics Reviews》2014,8(5):687-715
Because of long‐range order and high chemical purity, organic crystals have exhibit unique properties and attracted a lot of interest for application in solid‐state lasers. As optical gain materials, they exhibit high stimulated emission cross section and broad tunable wavelength emission as similar to their amorphous counterpart; moreover, high purity and high order give them superior properties such as low scattering trap densities, high thermal stability, as well as highly polarized emission. As electronic materials, they are potentially able to support high current densities, thus making it possible to realize current driven lasers. This paper mainly describes recent research progress in organic semiconductor laser crystals. The building molecules, crystal growth methods, as well as their stimulated emission characteristics related with crystal structures are introduced; in addition, the current state‐of‐the‐art in the field of crystal laser devices is reviewed. Furthermore, recent advances of crystal lasers at the nanoscale and single crystal light‐emitting transistors (LETs) are presented. Finally, an outlook and personal view is provided on the further developments of laser crystals and their applications. 相似文献
153.
154.
Huang WX Zhang Y Tang XM Cai LS Zhao JW Zhou L Wang QJ Huang CP Zhu YY 《Optics letters》2011,36(17):3359-3361
The optical properties of a planar metamaterial with gammadion-shaped chiral symmetry breaking holes array have been investigated both theoretically and experimentally. The results indicate that the introduction of the chiral symmetry breaking causes the split of the transmission peak and exerts large influence on the optical rotation and circular dichroism. Our metamaterials might have potential applications in future design of plasmonic devices. 相似文献
155.
A novel method of obtaining shearing interferogram by slightly moving the crystal in a photorefractive interferometer is proposed. This method can measure the phase of an object itself instead of its diffraction field, and it is easy to realize continuously changeable shearing distance in any lateral direction and introduce carrier fringes at the same time. Both the theoretical analysis and experimental verification are given. 相似文献
156.
Four new donor-acceptor-donor anthraquinone derivatives were synthesized and characterized by UV, IR, 1H NMR and elemental analysis. Their off-resonant third-order nonlinear optical properties were measured using femtosecond laser and degenerate four-wave mixing technique. The third-order nonlinear optical susceptibilities χ(3) were 3.36-3.76 × 10−13 esu. The nonlinear refractive indexes n2 were 6.19-6.91 × 10−12 esu. The second-order hyperpolarizabilities γ of the molecules were 3.36-3.76 × 10−31 esu. The response times were 101-115 fs. The results show that these compounds have potential nonlinear optical applications. 相似文献
157.
以商用金红石相TiO2粉末为原料,通过在碱性溶液中150℃水热48h的方法合成TiO2纳米管.采用SEM,TEM,XRD分析手段对TiO2纳米管的形貌和结构演变进行了表征.制成的TiO2纳米管与TritonX-100,乙酰丙酮混合后,通过丝网印刷的方法涂敷到ITO导电玻璃衬底上,并且在450℃下烧结30min后得到可应用于染料敏化太阳电池的多孔光阳极.将此光阳极浸泡于N719染料敏化后,与镀铂对电极组装电池,两者之间灌
关键词:
2纳米管')" href="#">TiO2纳米管
染料敏化太阳电池
水热法 相似文献
158.
159.
The calculations of the P-V isotherms, Hugoniots, dissociation and ionization degrees of fluid (liquid) hydrogen isotopes have been performed by using the self-consistent fluid variational theory under isothermal and shock compression. The isotope effect of fluid hydrogen was discussed. The present results are compared with the available experiments and calculations. 相似文献
160.
We propose and analyze experimentally a high-speed polarization-independent lead magnesium niobate titanate (PMNT) electro-optic switch using a π-shifted fiber Sagnac interferometer (FSI). In the proposed switch, the PMNT high-speed electro-optic ceramic is used as a phase retarder for two counterpropagating waves, which can switch the energy between the reflection and transmission ports of the FSI. Because of an initial π shift introduced into the FSI by actively adjusting the polarization controller, the power response of the switch is independent of the polarization orientation of the incident light, which induces the polarization-independent characteristic of the switch. An optical switch with cross talk lower than -25 dB and a switching time of less than 200 ns is experimentally investigated. The insertion loss and electric hysteresis property are also demonstrated. Finally, a scheme to form the n × n switch matrix is proposed. 相似文献