全文获取类型
收费全文 | 151篇 |
免费 | 1篇 |
专业分类
化学 | 69篇 |
力学 | 9篇 |
数学 | 6篇 |
物理学 | 68篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2013年 | 8篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 1篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有152条查询结果,搜索用时 15 毫秒
81.
Chumei Ye Dr. Lauren N. McHugh Celia Chen Prof. Siân E. Dutton Dr. Thomas D. Bennett 《Angewandte Chemie (International ed. in English)》2023,62(28):e202302406
Crystalline materials have governed the development of hybrid organic-inorganic perovskites (HOIPs), giving rise to a variety of fascinating applications such as solar cells and optoelectronic devices. With increasing interest in non-crystalline systems, the glassy state of HOIPs has recently been identified. Here, the basic building blocks of crystalline HOIPs appear to be retained, though their glasses lack long-range periodic order. The emerging family of glasses formed from HOIPs exhibits diverse properties, complementary to their crystalline state. This mini review describes the chemical diversity of both three-dimensional and two-dimensional crystalline HOIPs and demonstrates how glasses are produced from these materials. Specifically, current achievements in melt-quenched glasses formed from HOIPs are highlighted. We conclude with our perspective on the future of this new family of materials. 相似文献
82.
Thermal rearrangement of aminoimine, 1, followed by hydrogenation produced 1-phenyl-2-pyrrolidinyl cyclopentylamine 3. The structure and stereochemistry of this novel amine 4 was identified by x-ray crystallography of the 2-chloro-6-iodo-nicotinamide derivative as a hydrogen maleate salt.
83.
MP Janawadkar R Baskaran R Nagendran K Gireesan N Harishkumar Rita Saha L S Vaidhyanathan J Jayapandian Y Hariharan TS Radhakrishnan 《Pramana》2002,58(5-6):1159-1164
A program has been developed and initiated at the Indira Gandhi Centre for Atomic Research (IGCAR) for the utilization of
SQUID sensors in various application areas. DC SQUID sensors based on Nb-AlO
x
-Nb Josephson junctions have been designed and developed inhouse along with associated flux-locked loop (FLL) electronics.
A compact low field SQUID magnetometer insertible in a liquid helium storage dewar has also been developed inhouse and is
in use. Efforts to build a high field SQUID magnetometer, SQUID-DAC system, are in progress. A planar gradiometric DC SQUID
sensor for non-destructive evaluation (NDE) application to be used in relatively unshielded environment has been designed
and developed. An easily portable NDE cryostat with a small lift-off distance, to be used in external locations has been designed
and tested. The magnetic field produced by a given two-dimensional current density distribution is inverted using the Fourier
transform technique. 相似文献
84.
Christian T. McHugh Phillip G. Durham Michele Kelley Prof. Paul A. Dayton Prof. Rosa T. Branca 《Chemphyschem》2021,22(12):1219-1228
Gas microbubbles are an established clinical ultrasound contrast agent. They could also become a powerful magnetic resonance (MR) intravascular contrast agent, but their low susceptibility-induced contrast requires high circulating concentrations or the addition of exogenous paramagnetic nanoparticles for MR detection. In order to detect clinical in vivo concentrations of raw microbubbles via MR, an alternative detection scheme must be used. HyperCEST is an NMR technique capable of indirectly detecting signals from very dilute molecules (concentrations well below the NMR detection threshold) that exchange hyperpolarized 129Xe. Here, we use quantitative hyperCEST to show that microbubbles are very efficient hyperCEST agents. They can accommodate and saturate millions of 129Xe atoms at a time, allowing for their indirect detection at concentrations as low as 10 femtomolar. The increased MR sensitivity to microbubbles achieved via hyperCEST can bridge the gap for microbubbles to become a dual modality contrast agent. 相似文献
85.
86.
D.M. Newman M.L. Wears R.J. Matelon D. McHugh 《Applied physics. B, Lasers and optics》2002,74(7-8):719-722
The behaviour of the reflectivity and Kerr magneto-optic effects in the non-linear second-harmonic (SH) field diffracted from
nano-scale structured ferromagnetic interfaces is reported. Measurements are made in both the linear and non-linear fields
at two different fundamental wavelengths (1064 nm and 800 nm) and their associated harmonics. Resonant behaviour observed
as a function of angle of incidence is identified with surface-plasmon production that is known to intensify the local field
within the interface. Radiation incident at angles of incidence that optimise coupling to the electron plasma produces an
increase in the SH field radiated in the vicinity of those angles. Similarly, at those angles of incidence where radiation
at the SH wavelengths (532 nm and 400 nm) couples optimally to the electron plasma, troughs are seen in the angular spectrum
of the generated SH radiation. Kerr magneto-optic measurements taken in both the linear field and the SH field both show very
significant enhancement at angles meeting the plasma-resonance condition. The totality of experimental data presented allows
the conclusion that intensification of the interface electric field due to plasmon creation enhances not only the SH reflection
coefficient, as was already known, but also the magneto-optic reflection coefficients in both linear and SH fields.
Received: 16 October 2001 / Revised version: 14 March 2002 / Published online: 29 May 2002 相似文献
87.
John P. McHugh 《Applied Mathematics Letters》2011,24(7):1069-1074
Weakly nonlinear internal waves in an unbounded non-Boussinesq flow with uniform stratification are treated with a Laurent-type expansion. The expansion eliminates the problem encountered with a traditional expansion in wave amplitude where higher harmonics grow exponentially faster with higher order. The results show that the second-order wave correction to the linear estimate of the wave speed of internal waves in an unbounded layer is always negative, meaning that higher amplitude waves travel slower. 相似文献
88.
MP Blencowe 《Contemporary Physics》2013,54(4):249-264
Nanoelectromechanical systems (NEMS) are nano-to-micrometer scale mechanical resonators coupled to electronic devices of similar dimensions. NEMS show promise for fast, ultrasensitive force microscopy and for deepening our understanding of how classical dynamics arises by approximation to quantum dynamics. This article begins with a survey of NEMS and then describes certain aspects of their classical dynamics. In particular, we show that for weak coupling the action of the electronic device on the mechanical resonator can be effectively that of a thermal bath, this despite the device being a driven, far-from-equilibrium system. 相似文献
89.
Giang Huong Nguyen Thomas S. Dexheimer Andrew S. Rosenthal Wai Kit Chu Dharmendra Kumar Singh Georgina Mosedale Csanád Z. Bachrati Lena Schultz Masaaki Sakurai Pavel Savitsky Mika Abu Peter J. McHugh Vilhelm A. Bohr Curtis C. Harris Ajit Jadhav Opher Gileadi David J. Maloney Anton Simeonov Ian D. Hickson 《Chemistry & biology》2013,20(1):55-62
90.
The electro-oxidation of sulfate solutions is a well-established route for the generation of powerful oxidants such as persulfate. Despite this, the effects of simultaneous ultrasound irradiation during this process has attracted little attention. Herein, we investigate the effects of a low-intensity ultrasonic field on the generation of solution-phase oxidants during the electro-oxidation of sulfate solutions. Our results show that at high current densities and high sulfate concentrations, ultrasound has little effect on the Faradaic and absolute yields of solution-phase oxidants. However, at lower current densities and sulfate concentrations, the amount of these oxidants in solution appears to decrease under ultrasonic irradiation. A mechanism explaining these results is proposed (and validated), whereby anodically-generated sulfate and hydroxyl radicals are more effectively transported into bulk solution (where they are quenched) during sonication, whereas in the absence of an ultrasonic field these radicals combine with one another to form more persistent species (such as persulfate) that can be detected by iodometry. 相似文献