全文获取类型
收费全文 | 293篇 |
免费 | 1篇 |
国内免费 | 4篇 |
专业分类
化学 | 150篇 |
晶体学 | 2篇 |
力学 | 3篇 |
数学 | 45篇 |
物理学 | 98篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 6篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 20篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 11篇 |
2007年 | 10篇 |
2006年 | 16篇 |
2005年 | 7篇 |
2004年 | 16篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 15篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1970年 | 3篇 |
1959年 | 2篇 |
1944年 | 2篇 |
1933年 | 1篇 |
排序方式: 共有298条查询结果,搜索用时 15 毫秒
51.
C. A. Londos M. S. Potsidi J. Bak‐Misiuk A. Misiuk V. V. Emtsev 《Crystal Research and Technology》2003,38(12):1058-1062
The effect of enhanced hydrostatic pressure following heat treatment on the evolution of point defects in neutron‐irradiated Czochralski‐grown silicon is investigated using infrared spectroscopy. The behavior of oxygen‐related defects, particularly of the VO and the VO2 centers, is mainly studied using samples subjected to heat treatment under hydrostatic pressure. It is observed that (1) pressure accelerates the annealing process of the VO defects and enhances the growth of the VO2 complexes and (2) the VO2 concentration is larger than expected from the corresponding decay of the VO defects. The faster decay of the VO defects is attributed to a pressure‐induced decrease of their migration energy. The larger VO2 concentration is also discussed. One possible explanation is that pressure stimulates an additional mechanism for the formation of the VO2 defects, which involves the reaction of oxygen dimers with vacancies. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
52.
The molecular and vibrational structure of the title compound (C4-HSL) was studied by experimental and theoretical methods. The infrared (IR) absorption spectrum was measured in the solid state and in CCl4 suspension. The observed absorption bands were compared with transitions obtained with B3LYP/cc-pVTZ density functional theory (DFT) calculations. Two stable molecular conformations were predicted, corresponding to an endo- and an exo-conformer with similar energies. Intermolecular amide–amide hydrogen bonding in the crystal state was approximated by a simple cluster model, leading to excellent agreement with the observed solid state IR spectrum. Due to the low solubility of C4-HSL in common solvents for IR spectroscopy, such as CS2 and CCl4, a liquid solution spectrum of pure, monomeric C4-HSL was not obtained. However, absorbance peaks observed in oversaturated CCl4 solution could be assigned to distinct contributions from suspended micro-crystalline aggregates and dissolved monomeric species. The key vibrational bands of the monomeric form of C4-HSL are reported here for the first time: 3425 cm?1 [ν(N–H)], 1784 cm?1 [ν(CO), lactone], 1688 cm?1 [amide I], and 1494 cm?1 [amide II] (CCl4). 相似文献
53.
Sang-Bok Ma Kyung-Wan Nam Won-Sub Yoon Seong-Min Bak Xiao-Qing Yang Byung-Won Cho Kwang-Bum Kim 《Electrochemistry communications》2009,11(8):1575-1578
Nano-sized lithium manganese oxide (LMO) dispersed on carbon nanotubes (CNT) has been synthesized successfully via a microwave-assisted hydrothermal reaction at 200 °C for 30 min using MnO2-coated CNT and an aqueous LiOH solution. The initial specific capacity is 99.4 mAh/g at a 1.6 C-rate, and is maintained at 99.1 mAh/g even at a 16 C-rate. The initial specific capacity is also maintained up to the 50th cycle to give 97% capacity retention. The LMO/CNT nanocomposite shows excellent power performance and good structural reversibility as an electrode material in energy storage systems, such as lithium-ion batteries and electrochemical capacitors. This synthetic strategy opens a new avenue for the effective and facile synthesis of lithium transition metal oxide/CNT nanocomposite. 相似文献
54.
Alim Mohammad A. Bak Tadeusz Atanacio Armand J. Ionescu Mihail Kennedy Brendan Price William S. Du Plessis Johan Pourmahdavi Maryam Zhou Meifang Torres Allan Nowotny Janusz 《Ionics》2017,23(12):3517-3531
Ionics - This work reports the effect of tantalum (0.1–1 at.% Ta) on the photocatalytic performance of TiO2 annealed at 1373 and 1673 K in air. It was shown that addition of... 相似文献
55.
Arzhannikov A. V. Bak P.A. Belousov V. I. Ginzburg N. S. Zaslavsky V.Yu. Nikiforov D.A. Peskov N.Yu. Sandalov E. S. Sinitsky S. L. Sobolev D. I. Starostenko A. A. Zhivankov K. I. 《Radiophysics and Quantum Electronics》2022,64(11):814-824
Radiophysics and Quantum Electronics - The high-power long-pulse submillimeter-wave free-electron laser (FEL) is developed jointly by the Institute of Nuclear Physics and the Institute of Applied... 相似文献
56.
M. Ijjaali K. Kowalski T. Bak B. Dupre C. Gleitzer J. Nowotny M. Rekas C. C. Sorrell 《Ionics》2001,7(4-6):351-359
This paper reports the results of the electrical conductivity measurements for polycrystalline specimens of undoped and Cr-doped
CoO in the ranges of p(O2) (10−5 – 105 Pa) and temperature (1223 – 1373 K). The experimental data are considered in terms of the effect of Cr on semiconducting
properties of CoO. It is shown that Cr results in a decrease of the reciprocal of the p(O2) exponent of electrical conductivity, however, the obtained experimental values are substantially lower than those predicted
by defect chemistry. The activation energy of the electrical conductivity remains independent of p(O2) and Cr content (at the level of about 0.5 eV) except strongly reduced CoO, at p(O2)=2.10−4 Pa, of which the activation energy is substantially higher. Thermopowervs p(O2) exhibits maximum at p(O2)=10 Pa (except of thermopower data for Cr-doped CoO at the highest temperature). The experimental data are considered in
terms of the effect of both p(O2) and Cr on semiconducting properties. 相似文献
57.
This paper considers electrical properties of La1−xSrxCoO3−δ in terms of defect models, such as random defect model and the cluster model. It is shown that the experimental data of the
electrical conductivity may be explained in terms of the random defect model rather than the cluster model. 相似文献
58.
J. Auleytner J. Bak Z. Furmanik M. Maciaszek A. Saulewicz 《Crystal Research and Technology》1980,15(3):301-304
In this paper the X-ray section topograph method was used for determination of damaged layer thickness of silicon crystal surface. For measurements such reflections should be chosen for which the “margine” effect is very sharp. It was used the fact that in the ranges of strong perturbances the approximation of kinematic theory could be applied. 相似文献
59.
60.
Zygmunt Bak 《Czechoslovak Journal of Physics》2003,53(1):5-9
We consider interlayer magnetic coupling in a superlattice and/or overlayer in the case when spacer layer has the tendency towards formation of the helical spin density wave. Within phenomenological Landau-Ginzburg approach we show that the mutual interplay of the SDW and interlayer coupling spin polarization can lead to the helical interlayer coupling. When surface anisotropy is accounted for the effective interaction mimics interlayer biquadratic coupling. 相似文献