全文获取类型
收费全文 | 2929篇 |
免费 | 107篇 |
国内免费 | 6篇 |
专业分类
化学 | 2151篇 |
晶体学 | 11篇 |
力学 | 47篇 |
数学 | 388篇 |
物理学 | 445篇 |
出版年
2023年 | 17篇 |
2022年 | 21篇 |
2021年 | 35篇 |
2020年 | 56篇 |
2019年 | 62篇 |
2018年 | 27篇 |
2017年 | 33篇 |
2016年 | 88篇 |
2015年 | 91篇 |
2014年 | 95篇 |
2013年 | 145篇 |
2012年 | 155篇 |
2011年 | 191篇 |
2010年 | 134篇 |
2009年 | 97篇 |
2008年 | 163篇 |
2007年 | 171篇 |
2006年 | 141篇 |
2005年 | 140篇 |
2004年 | 124篇 |
2003年 | 93篇 |
2002年 | 101篇 |
2001年 | 56篇 |
2000年 | 57篇 |
1999年 | 40篇 |
1998年 | 51篇 |
1997年 | 44篇 |
1996年 | 39篇 |
1995年 | 62篇 |
1994年 | 47篇 |
1993年 | 48篇 |
1992年 | 33篇 |
1991年 | 35篇 |
1990年 | 27篇 |
1989年 | 21篇 |
1988年 | 15篇 |
1987年 | 18篇 |
1986年 | 11篇 |
1985年 | 25篇 |
1984年 | 19篇 |
1983年 | 12篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 18篇 |
1979年 | 12篇 |
1978年 | 15篇 |
1977年 | 17篇 |
1975年 | 13篇 |
1973年 | 19篇 |
1972年 | 7篇 |
排序方式: 共有3042条查询结果,搜索用时 11 毫秒
81.
82.
83.
David Uhrig Ralf Schlegel Roland Weidisch Jimmy MaysAuthor vitae 《European Polymer Journal》2011,(4):560-568
The synthesis of well-defined multigraft copolymers having a polydiene backbone with polystyrene side chains is briefly reviewed, with particular focus on controlling branch point spacing and branch point functionality. Use of living anionic polymerization and chlorosilane linking chemistry has led to the synthesis of series of materials having regularly spaced trifunctional (comb), tetrafunctional (centipede), and hexafunctional (barbwire) branch points. The morphologies of these materials were characterized by transmission electron microscopy and small-angle X-ray scattering, and it was found that the morphologies were controlled by the local architectural asymmetry associated with each branch point. Mechanical properties studies revealed that such multigraft copolymers represent a new class of thermoplastic elastomers (TPEs) with superior elongation at break and low residual strains as compared to conventional TPEs. 相似文献
84.
The quantum group IGL
q
(N), the inhomogenization of GL
q
(N), is formulated with
-matrices. Theq-deformed universal enveloping algebra is constructed as the algebra of regular functionals in this formulation and contains the partial derivatives of the covariant differential calculus on the quantum space. 相似文献
85.
F. Renz V. Martinez M. Klein M. Schott T. Hoffmann M. Blumers I. Fleischer G. Klingelhöfer R. Boča M. Menzel 《Hyperfine Interactions》2008,184(1-3):259-265
The precursors [Fe(III)(N???R???L)Cl] (N???R???LH2=N,N′-bis(2′-hydroxy- 5′-methyl-benzyliden)-1,7-diamino-4-R-4-azaheptane, R ?=? H, methyl(Me)) are high-spin (S?=?5/2) complexes. The Lewis-acidic precursors are combined with Lewis- Base-bridging-units [M(CN) x ] y??? (M = Fe(II), Ru(II), Co(III)) to form heptanuclear star-shaped [M{CN-Fe(III)(N???R???L)} x ]Cl y molecular switches. The star-shaped compounds are high-spin systems at room temperature. On cooling to 20 K some of the compounds exhibit multistability, i.e. several iron(III) centers within a molecule switch to the low-spin state as shown by Mössbauer spectroscopy. 相似文献
86.
Menzel D Fastl H Graf R Hellbrück J 《The Journal of the Acoustical Society of America》2008,123(5):2477-2479
This experiment investigates the effect of images of differently colored sports cars on the loudness of a simultaneously perceived car sound. Still images of a sports car, colored in red, light green, blue, and dark green, were displayed to subjects during a magnitude estimation task. The sound of an accelerating sports car was used as a stimulus. Statistical analysis suggests that the color of the visual stimulus may have a small influence on loudness judgments. The observed loudness differences are generally equivalent to a change in sound level of about 1 dB, with maximum individual differences of up to 3 dB. 相似文献
87.
Patricia Dähmlow Torsten Trittel Kathrin May Kirsten Harth Ralf Stannarius 《Liquid crystals》2018,45(7):993-1003
Elongated freely floating smectic bubbles are observed during their relaxation to equilibrium sphere shape. Unlike soap bubbles that perform weakly damped oscillations into equilibrium, this relaxation is overdamped in smectics by internal structure reorganisation processes. The bubble area reduction of centimetre-sized freely floating bubbles with few nanometres film thickness is recorded with high-speed optical imaging in microgravity and analysed quantitatively. We find a nearly linear reduction of the film area with time, driven by capillary forces and inhibited by smectic layer reorganisations. Characteristic times are in the milliseconds range, with little correlation to the film thickness and bubble size. Instead, the homogeneity of the films and the number and sizes of islands of excess layers that spontaneously form on the films appear to have crucial influence on the dynamics. The efficiency of this process sets the time scale of the film area shrinkage. We discuss the limitations of a minimalistic model that captures smectic layer reorganisation processes. 相似文献
88.
89.
Two-Photon-Induced CO-Releasing Molecules as Molecular Logic Systems in Solution,Polymers, and Cells
Dr. Vadde Ramu Dr. Gandra Upendar Reddy Dr. Jingjing Liu Patrick Hoffmann Dr. Rudrakant Sollapur Dr. Ralf Wyrwa Dr. Stephan Kupfer Prof. Dr. Christian Spielmann Dr. Sylvestre Bonnet Prof. Dr. Ute Neugebauer Dr. Alexander Schiller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8453-8458
Phototherapeutic applications of carbon monoxide (CO)-releasing molecules are limited because they require harmful UV and blue light for activation. We describe two-photon excitation with NIR light (800 nm)-induced CO-release from two MnI tricarbonyl complexes bearing 1,8-naphthalimide units ( 1 , 2 ). Complex 2 behaves as a logic OR gate in solution, nonwovens, and in HeLa cells. CO release, indicated by fluorescence enhancement, was detected in solution, nonwoven, and HeLa cells by single- (405 nm) and two-photon (800 nm) excitation. The photophysical properties of 1 and 2 have been measured and supported by DFT and TDDFT quantum chemical calculations. Both photoCORMs are stable in the dark in solution and noncytotoxic, leading to promising applications as phototherapeutics with NIR light. 相似文献