全文获取类型
收费全文 | 22545篇 |
免费 | 5428篇 |
国内免费 | 2640篇 |
专业分类
化学 | 9052篇 |
晶体学 | 1056篇 |
力学 | 1223篇 |
综合类 | 162篇 |
数学 | 362篇 |
物理学 | 18758篇 |
出版年
2024年 | 54篇 |
2023年 | 147篇 |
2022年 | 454篇 |
2021年 | 477篇 |
2020年 | 510篇 |
2019年 | 432篇 |
2018年 | 492篇 |
2017年 | 744篇 |
2016年 | 911篇 |
2015年 | 863篇 |
2014年 | 1232篇 |
2013年 | 1965篇 |
2012年 | 1611篇 |
2011年 | 1685篇 |
2010年 | 1339篇 |
2009年 | 1583篇 |
2008年 | 1702篇 |
2007年 | 1714篇 |
2006年 | 1679篇 |
2005年 | 1421篇 |
2004年 | 1275篇 |
2003年 | 1098篇 |
2002年 | 1017篇 |
2001年 | 874篇 |
2000年 | 843篇 |
1999年 | 715篇 |
1998年 | 621篇 |
1997年 | 595篇 |
1996年 | 473篇 |
1995年 | 442篇 |
1994年 | 372篇 |
1993年 | 265篇 |
1992年 | 250篇 |
1991年 | 170篇 |
1990年 | 136篇 |
1989年 | 92篇 |
1988年 | 84篇 |
1987年 | 74篇 |
1986年 | 39篇 |
1985年 | 42篇 |
1984年 | 33篇 |
1983年 | 16篇 |
1982年 | 25篇 |
1981年 | 12篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1970年 | 3篇 |
1957年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
S. B. Bushuk Yu. A. Kal'vinkovskaya A. N. Rubinov 《Journal of Applied Spectroscopy》2004,71(2):291-294
Capture of an ensemble of polymeric microspheres in a water suspension under the action of optical gradient forces in the field of interfering laser beams has been investigated for the case of two-, three-, and four-beam interference. The self-diffraction and diffraction of radiation on induced ordered spatial distribution of particles have been obtained. 相似文献
52.
O. Hugon 《Fiber and Integrated Optics》2003,22(5):283-288
A very simple and efficient technique for the remote sensing of a noncooperative target is presented. This technique is based on the frequency-shifted reinjection of light in a class B laser. Ytterbium- and erbium-doped fiber lasers have both been used to measure displacements with a submicrometric resolution and the vibration power spectrum of an object. 相似文献
53.
为了使光盘获得优良的记录/读出性能并能够长期稳定地使用,必须优化设计相变光盘的多层膜结构。采用自行设计的模拟分析相变光盘读出过程设计软件,从光学角度出发模拟计算了蓝光(405nm)相变光盘的膜层结构,研究了多层膜系的反射率和反射率对比度等光学参量与各层膜厚度和槽深的关系。研究得出的最佳多层膜结构为:下介电层/记录层/上介电层/反射层的厚度对于台记录为100nm/10nm/25nm,/60nm,而对于槽记录则为140nm/15nm/30nm,/60nm,槽深为50nm。模拟计算结果对于将来高密度蓝光相变光盘的制备具有一定的指导意义。 相似文献
54.
By using the methods of the matrix decomposition and expansion of the hard-edged aperture function into a finite sum of complex Gaussian functions, the recurrence propagation expressions for a flattened Gaussian beam (FGB) through multi-apertured optical imaging systems of B = 0 are derived and illustrated with numerical examples. Comparisons with the straightforward numerical integration of the Collins formula and with the previous work are made. It is shown that the main advantages of our methods and results are the more accuracy and great reduction of computer time. 相似文献
55.
A solution to the phase problem in optics is considered within the context of registration and analysis of two-dimensional stationary optical fields transformed by the object under study or fields forming an image. To obtain information on amplitude and phase distributions of the light field analyzed, a method of registration of two intensity distributions is used. The first distribution corresponds directly to the amplitude distribution. The other is formed for the sum of the initial field and the field shifted along a certain direction. The intensity distributions obtained allow one to calculate the two-dimensional structure of the field under study. It is noteworthy that the method requires no iteration procedures in solving the problem. This leads to speeding up of the processing and analysis of the information. Two variants of optical schemes for the analysis of light fields are considered. The first one corresponds to registration of the image of the analyzed plane and the second to registration of the spectrum of the spatial frequencies. 相似文献
56.
A glass fiber piezooptical optical bistability device is reported.Basing on pho-toelastic and strain effects of single-mode fiber,we have realized piezooptical modulation andperformed experiments of optical bistability. 相似文献
57.
58.
In photochemical vapor deposition of aluminum film on silicon using dimethylaluminum hydride, (CH3)2AlH, a surface reaction dominated below a (CH3)2AlH pressure of 0.3 m Torr at 200°C, which was induced only with the 160 nm band emitted from a deuterium lamp. A gas-phase reaction occurred above 0.3 mTorr at 200°C, which could be induced by both 160 nm and 240 nm emission bands from the lamp. To distinguish between surface ad gas-phase reactions, a thickness profile was used. At 240°C the surface reaction could be induced even by the 240 nm band, while the deposits formed under illumination of the two bands were thinner than those obtained with only the 240 nm band, indicating occurrence of vacuum ultraviolet (VUV)-enhanced desorption. The mechanism responsible for the observed wavelength dependence in unclear. The electrical resistivity of the films deposited at 200°C was 4.5 μΩ cm, which did not change with wavelength. 相似文献
59.
Traveling wave Ti:LiNbO3 Mach-Zehnder optical modulators with buried electrodes and etched grooves in the SiO2 buffer layer are analyzed by the finite element method. The tradeoff between the bandwidth BW and the half-wave voltage Vπ is discussed. The value of BW/Vπ is used to weight the total performance of the modulator. Taking a thick buffer layer and etching deep grooves in the buffer layer are demonstrated as two effective methods to improve the performance of the modulator. A 3-dB optical bandwidth of 18 GHz with half-wave voltage 5V at a wavelength of 1.55 pm could be obtained even though the electrode is not very thick. When the requirement of half-wave voltage is not very critical, a bandwidth of more than 100 GHz can be obtained. 相似文献
60.