全文获取类型
收费全文 | 381篇 |
免费 | 156篇 |
国内免费 | 23篇 |
专业分类
化学 | 67篇 |
晶体学 | 6篇 |
力学 | 60篇 |
综合类 | 8篇 |
数学 | 9篇 |
物理学 | 410篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 21篇 |
2021年 | 15篇 |
2020年 | 19篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 17篇 |
2016年 | 20篇 |
2015年 | 19篇 |
2014年 | 49篇 |
2013年 | 31篇 |
2012年 | 46篇 |
2011年 | 35篇 |
2010年 | 25篇 |
2009年 | 19篇 |
2008年 | 18篇 |
2007年 | 16篇 |
2006年 | 25篇 |
2005年 | 28篇 |
2004年 | 11篇 |
2003年 | 14篇 |
2002年 | 11篇 |
2001年 | 20篇 |
2000年 | 9篇 |
1999年 | 9篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 4篇 |
排序方式: 共有560条查询结果,搜索用时 15 毫秒
1.
Yu. Satov B. Sharkov H. Haseroth Yu. Smakovski K. Makarov S. Kondrashev V. Roerich A. Stepanov H. Kugler R. Scrivens O. Camut A. Shumshurov A. Balabaev A. Charushin 《Journal of Russian Laser Research》2004,25(3):205-216
Experimental and numerical calculation results devoted to development of an optical system for an ion source based on a repetition rate CO2 laser are described. The laser chain consists of a master oscillator, gas absorber cells, and a four-pass amplifier. The optical system provides smooth laser pulses with variable duration and high spatial quality that ensures efficiency for plasma heating and ion generation. The parameters of the plasma ion component measured in the CERN laboratory are applied for a lead target illumination. 相似文献
2.
We report on the simultaneous generation of phase-conjugate signals by degenerate four-wave mixing (DFWM) and holographic processes using a nanosecond pulse and a CW lasers in polyvinyl alcohol (PVA) films doped with four kinds of saturable absorbing dyes. For the pulse laser, of the four kinds of dye-doped PVA films, the erythrosine B-doped PVA and uranine doped-PVA films generate PC signals only by the DFWM process, while the other dye-doped PVA films generate PC signals simultaneously by not only the DFWM process but also the holographic process. Especially, the safranin T-doped PVA film generates strong PC signals by the holographic process. In contrast, all of the dye-doped PVA films generate the two types of PC signals for the CW laser. The fading of dye molecules is found to result in the generation of the holographic component of PC signals which governs the temporal behavior of the total PC signals. 相似文献
3.
4.
By using a passive Q-switch with GaAs saturable absorber, the Q-switched self-frequency doubling NYAB laser at 0.531μm has been successfully realized. The pulse width and the single pulse energy are measured. The numerical solutions of the coupling wave rate equations are in agreement with the experimental results. 相似文献
5.
利用固体可饱和吸收体砷化镓(GaAs)作为被动调Q元件,实现了激光二极管抽运平-凹腔掺钕钒酸钇(Nd:YVO4)激光调Q运转,详细测量了砷化镓被动调QNd:YVO4激光输出特性,获得脉宽15ns,重复频率470kHz,光束质量M^2=1.31的激光输出,调Q激光运转阈值为500mW,并数值求解了砷化镓被动调Q速率方程,讨论了被动调Q机理以及调Q脉冲宽度和脉冲重复频率对抽运速率的依赖关系,理论计算结果与实验结果相一致。 相似文献
6.
The intensity dynamics of the double-clad Yb fibre laser have been characterised. Stabilisation of the fibre laser intensity by using uniform bi-directional pumping is demonstrated. For the single-end-pumped Yb fibre laser, the output becomes more stable for the shorter fibre length due to the higher threshold of stimulated Brillouin scattering, SBS, and Kerr effects and the reduction of saturated absorber effects caused by any unpumped fibre section. By additional pumping in a double-end-pumped configuration, the output power can be scaled higher before detecting high intensity pulses initiated by SBS in the Yb fibre laser due to the reduction of saturable absorption effect. It is confirmed that uniform pumping enhances the stability of the laser output. 相似文献
7.
A diode-end-pumped Nd:YAG laser is passively Q-switched by using Cr4+:YAG as saturable absorber. When CW pumped with a laser diode which the maximum power is 550 mW, the laser produces pulses of 24 ns duration at 1064 nm, with an energy of 26 μJ. 相似文献
8.
《Arabian Journal of Chemistry》2020,13(12):8848-8887
Phthalocyanine (Pc) complexes are an important class of dyes with numerous (e.g., biological, photophysical, and analytical) applications. Among the methods used to improve the properties of these complexes, one should mention the introduction of different substituents, variation of the central metal ion, ligand exchange, and conjugation to nanomaterials (e.g., carbon-based nanomaterials and metal nanoparticles (NPs)). This work briefly reviews Pc complex conjugation to Ag and Au NPs, highlights the different NP shapes, and discusses the diversity of conjugation approaches. Moreover, the use of UV–Vis spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering and Fourier transform infrared spectroscopy to characterize Pc-NP hybrids is summarized. The effect of conjugation on Pc photo-physicochemical properties (fluorescence, singlet oxygen generation, triplet state formation, and optical limiting behavior) is discussed, and future perspectives for the synthesis and applications of new hybrids are provided. 相似文献
9.
Schell J. Felder D. Nierengarten J.-F. Rehspringer J.-L. Lévy R. Hönerlage B. 《Journal of Sol-Gel Science and Technology》2001,22(3):225-236
Porous sol-gel glasses, either impregnated with pure C60 or doped with a methanofullerene derivative, have been studied and induced absorption or reverse saturable absorption (RSA) has been observed in both types of solid materials. The samples impregnated by pure C60 mainly contain well-dispersed fullerene molecules. Unlike crystalline films of C60, their absorption dynamics can be well described by a 5-level model, developed for non-interacting C60-molecules in solutions. Methanofullerene samples, on the other hand, show signs of micellar aggregation and therefore RSA dynamics that are influenced by solid state effects. We observe an important decrease of transmission at high fluences for both kinds of samples, a shortened singlet-state lifetime to that observed in solution, but nonetheless, a triplet yield, that cannot be considered as negligible. In the case of pure C60 in a sol-gel matrix, we can explain the faster de-excitation dynamics, relative to behavior in solution, mainly by the absence of stabilizing aromatic solvents and also by the interaction of the amorphous environment with the molecules. Concerning the methanofullerene samples, the acceleration of the de-excitation dynamics can be principally attributed to solid-state effects due to the micellar aggregation. 相似文献
10.
Black phosphorus saturable absorber for ultrafast mode‐locked pulse laser via evanescent field interaction
下载免费PDF全文
![点击此处可从《Annalen der Physik》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kichul Park Junsu Lee Young Tack Lee Won‐Kook Choi Ju Han Lee Yong‐Won Song 《Annalen der Physik》2015,527(11-12):770-776
Black phosphorus, or BP, has found a lot of applications in recent years including photonics. The most recent studies have shown that the material has an excellent optical nonlinearity useful in many areas, one of which is in saturable absorption for passive mode‐locking. A direct interaction scheme for mode‐locking, however, has a potential to optically cause permanent damage to the already delicate material. Evanescent field interaction scheme has already been proven to be a useful method to prevent such danger for other 2‐dimensional nanomaterials. In this report, we have utilized the evanescent field interaction to demonstrate that the optical nonlinear characteristics of BP is sufficiently strong to use in such an indirect interaction method. The successful demonstration of the passive mode‐locking operation has generated pulses with the pulse duration, repetition rate, and time bandwidth product of 2.18 ps, 15.59 MHz, and 0.336, respectively. 相似文献