全文获取类型
收费全文 | 850篇 |
免费 | 26篇 |
国内免费 | 2篇 |
专业分类
化学 | 699篇 |
晶体学 | 3篇 |
力学 | 6篇 |
数学 | 70篇 |
物理学 | 100篇 |
出版年
2023年 | 3篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 15篇 |
2014年 | 18篇 |
2013年 | 33篇 |
2012年 | 44篇 |
2011年 | 59篇 |
2010年 | 31篇 |
2009年 | 29篇 |
2008年 | 48篇 |
2007年 | 64篇 |
2006年 | 61篇 |
2005年 | 39篇 |
2004年 | 48篇 |
2003年 | 46篇 |
2002年 | 47篇 |
2001年 | 7篇 |
2000年 | 13篇 |
1999年 | 9篇 |
1998年 | 13篇 |
1997年 | 6篇 |
1996年 | 18篇 |
1995年 | 4篇 |
1994年 | 15篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1972年 | 4篇 |
排序方式: 共有878条查询结果,搜索用时 31 毫秒
791.
Uto T Nishinaga T Matsuura A Inoue R Komatsu K 《Journal of the American Chemical Society》2005,127(29):10162-10163
An entirely new naphthalene having one six-membered ring, whose bond lengths are equalized, and another ring, whose bond lengths are alternated, has been prepared via one-electron oxidation of a benzene annelated with three bicyclo[2.1.1]hexene units. The structure has been determined by X-ray crystallography and the aromaticity of two benzene rings estimated by theoretical calculations. Although the former six-membered ring has a higher degree of aromaticity, it has been found to be more reactive toward singlet oxygen owing to the greater strain contained in it. These results have been interpreted by means of theoretical calculations. 相似文献
792.
Takahisa Anada Masako Ogawa Hisashi Yokomizo Yoshihisa Ozaki Tohru Takarada Yoshiki Katayama Mizuo Maeda 《Analytical sciences》2003,19(1):73-77
We describe here a method of affinity capillary electrophoresis in which oligodeoxynucleotide (ODN) was immobilized onto the inner surface of the capillary. The immobilized ODN functioned successfully as an affinity ligand for sequence-based DNA separation. Six- or 12-mer ODN with a sequence complementary to one of the c-K-ras gene was used as an immobilized ligand. When the 12-mer ODN was used, the detection peak for the complementary ODN disappeared selectively, while the single-base mutant was detected as usual. In contrast, when the 6-mer ODN was used as the affinity ligand with a mixture of the complementary ODN and its single-base mutant, it was possible to detect both as completely separate peaks. That is, the separation mode was dependent on the base number of the immobilized ODN used as an affinity ligand. 相似文献
793.
Masayuki Masuko Takuji Kataoka Norikazu Sugiyama Shigeru Uchiyama Hirofumi Sugiyama Katsunori Tarui Kiyoshi Kamiya Tohru Kawai † 《Photochemistry and photobiology》1992,56(1):107-111
Abstract— We developed a photon counting TV camera system, which uses an image guide consisting of tapered optical fibers, for the rapid detection and counting of microscopic sized luminous particles in a wide field. Using a luminous bacterium as a standard, we compared this image guide-coupled TV camera to a lens-coupled TV camera by determining their light collecting powers and detection abilities for single bacteria on a membrane filter. The image guide shortened the detection time by an order of magnitude, making the photon counting TV camera a practical system for rapid counting of bacteria. 相似文献
794.
The Anderson transition is investigated using a self-consistent approximation in analogy with mean-field approximations in classical spin systems. Mobility edge trajectories in a three-dimensional disordered system with various distributions of the site energies are obtained. The present results are qualitatively in good agreement with the results obtained by using the finite-size scaling method. 相似文献
795.
We have found a form of copper(II) terephthalate that occluded an enormous amount of gases such as N2, Ar, O2, and Xe. Copper(II) terephthalate is the first metal complex found capable of adsorbing gases. This complex has opened a new field of adsorbent chemistry and is recognized as a leader in the construction of microporous metal complexes. In extending the route for the synthesis of microporous complexes, we obtained many new porous materials that are widely recognized as useful materials for applications in areas such as gas storage, molecular sieves, catalysis, inclusion complexes, and surface science. 相似文献
796.
Nakano T Nakagawa O Tsuji M Tanikawa M Yade T Okamoto Y 《Chemical communications (Cambridge, England)》2004,(2):144-145
Poly(2,7-di-n-pentyldibenzofulvene)s with no stereocenters, obtained by anionic polymerization using chiral 9-fluorenyllithium ligand complexes, showed intense circular dichroism in film form due purely to the chiral conformation of the main chain, while no chiroptical properties were detectable in solution. 相似文献
797.
Monde K Taniguchi T Miura N Nishimura S 《Journal of the American Chemical Society》2004,126(31):9496-9497
The vibrational circular dichroism (VCD) technique was applied to carbohydrates and produced a glycoside characteristic VCD band, which was named the "glycoside band." It confirmed that this vibration was related to anomeric configurations of carbohydrates in the case of the d-series by means of isotope substitution. This band is defined as a negative, sharp, and intense VCD band at around 1145 cm-1, exhibited by d-sugars with an axial alpha-glycosidic linkage in the 4C1 conformation. As applications of this band, the VCD studies of the maltose-cellobiose mixture and the monitoring of the amyloglucosidase reaction were examined. 相似文献
798.
Reika Fukuizumi Tohru Ozawa 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2005,56(6):1000-1011
Exponential decay estimates are obtained for complex-valued solutions to nonlinear elliptic equations in
where the linear term is given by Schr?dinger operators H = − Δ + V with nonnegative potentials V and the nonlinear term is given by a single power with subcritical Sobolev exponent in the attractive case. We describe specific
rates of decay in terms of V, some of which are shown to be optimal. Moreover, our estimates provide a unified understanding of two distinct cases in
the available literature, namely, the vanishing potential case V = 0 and the harmonic potential case V(x) = |x|2.
Dedicated to Professor Jun Uchiyama on the occasion of his sixtieth birthday
Received: May 4, 2004 相似文献
799.
We measured the time evolutions of the luminescence spectra in a quasi-1D halogen-bridged platinum complex [Pt(en)(2)][Pt(en)(2)Br(2)](ClO4)(4) with a 50 fs resolution up-conversion spectroscopy and succeeded in real-time visualization of the shape of the wave packet (WP) propagating on the adiabatic potential surface of a self-trapped exciton. The behavior of the WP is in excellent agreement with a calculation based on a harmonic oscillator. We have found that the damping of the WP oscillation is highly nonexponential. 相似文献
800.
In this paper we present an interpolation inequality in the homogeneous Besov spaces on , which reduces to a number of well-known inequalities in special cases.