全文获取类型
收费全文 | 348篇 |
免费 | 3篇 |
专业分类
化学 | 161篇 |
晶体学 | 1篇 |
力学 | 14篇 |
数学 | 62篇 |
物理学 | 113篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 11篇 |
2020年 | 6篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 3篇 |
2013年 | 15篇 |
2012年 | 13篇 |
2011年 | 17篇 |
2010年 | 7篇 |
2009年 | 10篇 |
2008年 | 6篇 |
2007年 | 17篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 16篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1996年 | 10篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 4篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1981年 | 10篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1970年 | 2篇 |
1942年 | 2篇 |
1902年 | 1篇 |
1889年 | 1篇 |
1887年 | 1篇 |
排序方式: 共有351条查询结果,搜索用时 15 毫秒
121.
Gazeau–Klauder coherent states examined from the viewpoint of diagonal ordering operation technique
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this paper we investigate the Gazeau–Klauder coherent states using a newly introduced diagonal ordering operation technique, in order to examine some of the properties of these coherent states. The results coincide with those obtained from other purely algebraic methods, but the calculations are greatly simplified. We apply the general theory to two cases of Gazeau–Klauder coherent states: pseudoharmonic as well as the Morse oscillators. 相似文献
122.
P. Viktorovitch B. Ben Bakir S. Boutami J. Louis Leclercq X. Letartre P. Rojo‐Romeo C. Seassal M. Zussy L. Di Cioccio J.Marc Fedeli 《Laser \u0026amp; Photonics Reviews》2010,4(3):401-413
It is emphasized that two‐dimensional photonic crystals (2D PC) have not only a great potential for the development of 2D nanophotonics in the inplane waveguided configuration, but that they may also open the way to other brilliant developments, with an extension to out‐of‐plane operation, along a 2.5D nanophotonics approach. In this 2.5D approach, a 1D–2D high index contrast lateral structuration is combined with a 1D high index contrast vertical structuration, using multilayer membrane stacks including 1D–2D photonic crystal membranes, thus resulting in so‐called 2.5D PC. As a specific illustration of recent achievements along this approach, new families of VCSEL structures are presented. 相似文献
123.
A bistable nonlinear energy sink conceived to mitigate the vibrations of host structural systems is considered in this paper. The hosting structure consists of two coupled symmetric linear oscillators (LOs), and the nonlinear energy sink (NES) is connected to one of them. The peculiar nonlinear dynamics of the resulting three-degree-of-freedom system is analytically described by means of its slow invariant manifold derived from a suitable rescaling, coupled with a harmonic balance procedure, applied to the governing equations transformed in modal coordinates. On the basis of the first-order reduced model, the absorber is tuned and optimized to mitigate both modes for a broad range of impulsive load magnitudes applied to the LOs. On the one hand, for low-amplitude, in-well, oscillations, the parameters governing the bistable NES are tuned in order to make it functioning as a linear tuned mass damper (TMD); on the other, for high-amplitude, cross-well, oscillations, the absorber is optimized on the basis of the invariant manifolds features. The analytically predicted performance of the resulting tuned bistable nonlinear energy sink (TBNES) is numerically validated in terms of dissipation time; the absorption capabilities are eventually compared with either a TMD and a purely cubic NES. It is shown that, for a wide range of impulse amplitudes, the TBNES allows the most efficient absorption even for the detuned mode, where a single TMD cannot be effective. 相似文献
124.
Minardo A Bernini R Urbanczyk W Wojcik J Gorbatov N Tur M Zeni L 《Optics letters》2008,33(20):2329-2331
We report on an experimental analysis of stimulated Brillouin scattering (SBS) in a 20-m-long highly birefringent microstructure fiber for sensing applications. In particular, an experimental setup based on Brillouin optical frequency-domain analysis, operating at a wavelength of 1550 nm, has been employed in order to analyze the distribution of Brillouin frequency shift along the fiber, as well as to study the dependence of Brillouin frequency shift on optical polarization, temperature, and strain. Our results indicate that, for any fixed polarization, the fiber has a dual-peaked Brillouin spectrum. A study about the origin of these two peaks is presented. 相似文献
125.
Valeria Ciaffaglione Valeria Consoli Sebastiano Intagliata Agostino Marrazzo Giuseppe Romeo Valeria Pittal Khaled Greish Luca Vanella Giuseppe Floresta Antonio Rescifina Loredana Salerno Valeria Sorrenti 《Molecules (Basel, Switzerland)》2022,27(10)
This paper reports on a novel series of tyrosine kinase inhibitors (TKIs) potentially useful for the treatment of chronic myeloid leukemia (CML). The newly designed and synthesized compounds are structurally related to nilotinib (NIL), a second-generation oral TKI, and to a series of imatinib (IM)-based TKIs, previously reported by our research group, these latter characterized by a hybrid structure between TKIs and heme oxygenase-1 (HO-1) inhibitors. The enzyme HO-1 was selected as an additional target since it is overexpressed in many cases of drug resistance, including CML. The new derivatives 1a–j correctly tackle the chimeric protein BCR-ABL. Therefore, the inhibition of TK was comparable to or higher than NIL and IM for many novel compounds, while most of the new analogs showed only moderate potency against HO-1. Molecular docking studies revealed insights into the binding mode with BCR-ABL and HO-1, providing a structural explanation for the differential activity. Cytotoxicity on K562 CML cells, both NIL-sensitive and -resistant, was evaluated. Notably, some new compounds strongly reduced the viability of K562 sensitive cells. 相似文献
126.
A new high-order accurate staggered semi-implicit space-time discontinuous Galerkin(DG)method is presented for the simulation of viscous incompressible flows on... 相似文献
127.
Itzel C. Núez-García Linda G. Rodríguez-Flores Michelle H. Guadiana-De-Dios María D. Gonzlez-Hernndez Guillermo C. G. Martínez-vila Jos A. Gallegos-Infante Rubn Gonzlez-Laredo Walfred Rosas-Flores Victor J. Martínez-Gmez Romeo Rojas Ignacio Villanueva-Fierro Miriam Rutiaga-Quiones 《Molecules (Basel, Switzerland)》2022,27(12)
A comparative study was carried out on the chemical, structural and thermal properties of candelilla wax from four wax-producing communities in Mexico, which was obtained by two extraction processes, the conventional one using sulfuric acid (SA) and an eco-friendly alternative process using citric acid (CA) as the extracting agent. The waxes were analyzed by basic chemistry (acidity, saponification, ester indexes, and others), color, Fourier transform infrared spectroscopy (FTIR), Raman micro-spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and hardness and brittleness measurements. The waxes obtained by the environmentally friendly process showed differences in their physicochemical properties when compared to waxes from the conventional process. In addition, they showed some improvements, such as lighter shades and harder waxes, suggesting that the new environmentally friendly process is a viable option. 相似文献
128.
Ugo Amaldi 《Annali di Matematica Pura ed Applicata》1938,17(1):1-21
Commemorazione letta davanti alla Classe di Scienze fisiche, matematiche e naturali della Reale Accademia Nazionale dei Lincei
nell'adunanza del 5 dicembre 1937-XVI. 相似文献
129.
130.
Vectoring, used in VDSL2 to counteract FEXT, becomes less effective, or even ineffective, when users belong to different vectoring groups. This situation is common when the Regulator imposes sub-loop unbundling and users of uncoordinated service providers cause alien-FEXT. The sub-band vectoring (SBV) technique introduced here, avoids this situation and retains the vectoring benefits. We show SBV allows achieving up to 150 Mbit/s per user in downstream at 200 m from cabinet for VDSL2 profile-35b, with two concurrent service providers. We also introduce the concept of data-rate coverage representing the users’ percentage served at a given data-rate in the area. 相似文献