全文获取类型
收费全文 | 5742篇 |
免费 | 162篇 |
国内免费 | 9篇 |
专业分类
化学 | 4321篇 |
晶体学 | 74篇 |
力学 | 62篇 |
综合类 | 2篇 |
数学 | 176篇 |
物理学 | 1278篇 |
出版年
2023年 | 30篇 |
2021年 | 41篇 |
2020年 | 71篇 |
2019年 | 75篇 |
2018年 | 60篇 |
2017年 | 32篇 |
2016年 | 94篇 |
2015年 | 121篇 |
2014年 | 105篇 |
2013年 | 287篇 |
2012年 | 260篇 |
2011年 | 270篇 |
2010年 | 179篇 |
2009年 | 175篇 |
2008年 | 264篇 |
2007年 | 320篇 |
2006年 | 304篇 |
2005年 | 331篇 |
2004年 | 258篇 |
2003年 | 238篇 |
2002年 | 229篇 |
2001年 | 127篇 |
2000年 | 130篇 |
1999年 | 89篇 |
1998年 | 62篇 |
1997年 | 58篇 |
1996年 | 101篇 |
1995年 | 61篇 |
1994年 | 60篇 |
1993年 | 73篇 |
1992年 | 77篇 |
1991年 | 71篇 |
1990年 | 63篇 |
1989年 | 64篇 |
1988年 | 66篇 |
1987年 | 65篇 |
1986年 | 60篇 |
1985年 | 97篇 |
1984年 | 94篇 |
1983年 | 49篇 |
1982年 | 74篇 |
1981年 | 72篇 |
1980年 | 87篇 |
1979年 | 66篇 |
1978年 | 54篇 |
1977年 | 38篇 |
1976年 | 48篇 |
1975年 | 31篇 |
1974年 | 37篇 |
1973年 | 36篇 |
排序方式: 共有5913条查询结果,搜索用时 15 毫秒
41.
Kentaro Suzuki Taro Toyota Katsuhiko Sato Masakazu Iwasaka Shoogo Ueno Tadashi Sugawara 《Chemical physics letters》2007,440(4-6):286-290
Collagen-containing tubular giant vesicles (Col–tGVs) under a high static magnetic field were found to constitute characteristic curved structures (e.g. circular, 8-figure, and hairpin-loop), which were sustained by polymerization of collagen units inside the tGV. We ascribed the formation of these structures to the elasticity of the tGV and to the competing diamagnetic anisotropies between collagen and the tGV. These curved structures can be well expressed by the equation of elastica. 相似文献
42.
Kazuhiro Yamamoto Haruhiko Ito Kouki Totsuka Tomohiro Sato 《Optics Communications》2006,265(2):692-695
We consider a new scheme of optically ionizing atoms with 10-nm-order spatial resolution. In this method, two-color near-field lights are generated on a narrow slit illuminated by two-color evanescent lights via total-internal reflection of two-wavelength light beams. In order to illustrate the feasibility, we first obtain the ionization cross section from two-step photionization of cold Rb atoms by two-color evanescent lights on a plane surface of a prism. Then, we numerically estimate the ionization efficiency as a function of the slit width using Bethe formula. The scheme is useful for detecting ground-state atoms under less perturbation by scattered light. 相似文献
43.
Liquid crystal lens with focus movable in focal plane 总被引:1,自引:0,他引:1
A liquid crystal lens with focus movable in the focal plane is reported. There are three electrodes in the cell. One electrode with a hole in the center is divided into four subelectrodes. The potential of each subelectrode is adjusted to produce a desired asymmetrical phase transformation resulting in off-axis movement of the focus. The potential of another electrode is adjusted to maintain the focus in the focal plane. Movements of the focus in three directions in the focal plane are demonstrated experimentally, and off-axis movement as large as approximately 800 μm is realized. 相似文献
44.
The analytical method using transfer function or impulse response is very effective for analyzing non-linear systems with localized non-linearities. This is because the number of non-linear equations can be reduced to that of the equations with respect to points connected with the non-linear element. In the present paper, analytical method for the steady state vibration of non-linear system including subharmonic vibration is proposed by utilizing convolution integral and the impulse response. The Galerkin method is introduced to solve the non-linear equations formulated by the convolution integral, and then the steady state vibration is obtained. An advantage of the present method is that stability or instability of the steady state vibration can be discriminated by the transient analysis from convolution integral. The three-degree-of-freedom mass-spring system is shown as a numerical example and the proposed method is verified by comparing with the result by Runge-Kutta-Gill method. 相似文献
45.
Toshiyuki Oyama Akira Kitamura Eiichi Sato Masao Tomoi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(8):2694-2706
The factors affecting pattern‐forming properties in reaction development patterning were examined with polyarylates with various bisphenol moieties. The developability of the photosensitive polyarylates was dependent on the properties of the subtituent (R) in the bisphenol moieties. The development time decreased in the following order: R?C(CH3)2 > fluorenyl unit ? phenolphthalein unit > C(CF3)2 > SO2. This order agreed with that of the reactivity between the polyarylates and ethanolamine, and these orders can be explained by pKa of the bisphenol used to prepare the polyarylates. The development with NH2? R′? OH resulted in successful positive‐tone pattern formation. However, pattern formation with the developers containing NH2? R′? OCH3 was unsuccessful. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2694–2706, 2006 相似文献
46.
In this study, we attempted to control the timing of light-emission from bioluminescent bacteria, by changed cell numbers inoculated into medium. Luminous bacteria express bioluminescence when the number of cells reached a threshold. Inoculated cell density had an effect on the time of bioluminescence starting. Samples were prepared by varying cell density of inoculation. In the results, all the vials showed different luminescence profiles in the order of inoculated cell population. 相似文献
47.
48.
Haruo Sato 《Hyperfine Interactions》1990,57(1-4):2089-2094
Mössbauer spectra of ferrocene adsorbed on silica gel were measured in order to study the state of adsorption. Ferrocene adsorbed on silica gel tended to oxidize in air and form ferricenium ion. It is assumed that the oxidation of adsorbed ferrocene was caused by surface hydroxyls on the silica gel and O2 in air. It was observed that ferrocene adsorbed weakly at 293 K, although the ferricenium ion adsorbed strongly at 293 K. Thus the adsorption states of ferrocene depend on the experimental condition. 相似文献
49.
50.