全文获取类型
收费全文 | 458篇 |
免费 | 3篇 |
专业分类
化学 | 204篇 |
晶体学 | 12篇 |
力学 | 17篇 |
数学 | 22篇 |
物理学 | 206篇 |
出版年
2022年 | 5篇 |
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 16篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 18篇 |
2011年 | 22篇 |
2010年 | 17篇 |
2009年 | 14篇 |
2008年 | 19篇 |
2007年 | 17篇 |
2006年 | 20篇 |
2005年 | 17篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 3篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1975年 | 3篇 |
1973年 | 10篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1969年 | 6篇 |
1968年 | 5篇 |
排序方式: 共有461条查询结果,搜索用时 38 毫秒
1.
O. I. Kotov L. B. Liokumovich S. I. Markov A. V. Medvedev A. V. Khlybov 《Technical Physics》2004,49(1):71-75
Mechanisms of polarization modulation in a single-mode fiber that modulate the phase difference between polarization modes without affecting their amplitudes are considered. A coefficient that characterizes the efficiency of cylindrical piezoceramic modulators and is independent of their resonant properties is introduced. Analytical expressions for this coefficient for different modulation mechanisms are derived. The lateral pressure on the fiber is shown to provide the highest efficiency. For isotropic fibers, a modulator with a squeezing covering, which increases significantly its efficiency, is studied. For anisotropic fibers, the most appropriate way of phase difference modulation is longitudinal extension, in which case the birefringence axes do not have to be matched. In most cases, the measured and predicted efficiencies are in good correspondence. 相似文献
2.
Amorphous silver, copper, gold, and iron films of a thickness between 6 and 350 nm are grown on polymeric substrates by vacuum
evaporation. The nanostructure of the films is investigated. The dependence of the conductivity on the film thickness is obtained,
and a correlation between the surface morphology and the conductivity is established. 相似文献
3.
4.
5.
6.
V. I. Belotelov A. P. Pyatakov A. K. Zvezdin V. A. Kotov A. S. Logginov 《Technical Physics》2003,48(1):1-6
The images of magnetic and nonmagnetic nanoparticles obtained by scanning near-field microscopy in the photon collection mode
are numerically simulated. A theoretical approach that uses tensor electrodynamic Green’s functions to find the optical near
field in a given observation scheme is considered. Typicalimages of nanoparticles with various shapes are obtained by numerical
simulation. Subject to boundary conditions, the plane of polarization is shown to change at topographic features (edges and
angles) of objects studied. This makes the observation of the magnetic structure of a nanoparticle with a magnetooptic method
difficult. The near-field study of the magnetization distribution in homogeneous thin films appears to be more effective,
since the rotation of plane of polarization is associated primarily with the magnetic properties of the sample in this case. 相似文献
7.
V. A. Ozhiganov A. P. Kotov L. P. Andreeva L. P. Zelenin P. V. Gel'd 《Russian Physics Journal》1991,34(5):418-421
The effect of composition and temperature on the properties of the alloy PdV-20 doped with nickel was investigated. It was established that the microhardness, electroresistivity, and the normal elasticity modulus depend nonmonotonically on the content of nickel, and also that these quantities are affected significantly by the past thermal history of the samples. The results' are discussed, taking into account the nature of their intrinsic short-range order structure.Translated from Izvestiya Vysshikh. Uchebnykh Zavedenii, Fizika, No. 5, pp. 42–46, May, 1991. 相似文献
8.
A. N. Kost L. N. Khaimov Yu. Dzhurakulov K. Kh. Khaidarov L. D. Lebedeva A. L. Kotov 《Chemistry of Heterocyclic Compounds》1975,11(11):1263-1266
2-Substituted or 2,2-disubstituted 4,6-dioxo-1,3-dioxanes, which are analogs of Meldrum's acid and were obtained by reaction of malonic acid with acetic anhydride and the appropriate carbonyl compound in the presence of sulfuric acid, exist in solution preferably in a single form according to the PMR and 13C NMR spectral data. Fluctuation of the CH2 group is not observed. The mass spectra are characteristic and are distinguished by splitting out of the carbonyl compound from the molecular ion or successive splitting out of CO2 and ketene molecules. The Meldrum acid analogs do not affect plant growth but have a depressive effect on the central nervous system of animals and low toxicity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1482–1486, November, 1975. 相似文献
9.
10.
R. V. Pisarev V. V. Kalashnikov A. I. Kotov E. B. Yagubskii 《Russian Chemical Bulletin》1996,45(3):735-736
[2+4[-Cycloaddition of 2,3-dihydro-1,4-dithiine and oligomeric 1,3-dithiol-2,4,5-trithione results in the formation of 4a,6,7,8a-tetrahydro-1,3-dithiolo[4',5':5,61-[1,4[dithiino[2,3-b[1,4-dithiine-2-thione, which is a precursor for synthesis of new organic rz-donors.Translated fromIzvestiya Akademi Nauk Seriya Khimicheskaya No. 3, pp. 775–776, March, 1996. 相似文献