全文获取类型
收费全文 | 89篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 63篇 |
力学 | 1篇 |
数学 | 10篇 |
物理学 | 20篇 |
出版年
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1972年 | 2篇 |
1970年 | 1篇 |
1965年 | 1篇 |
1889年 | 1篇 |
排序方式: 共有94条查询结果,搜索用时 31 毫秒
91.
Mônica M. Linn 《Tetrahedron letters》2007,48(26):4547-4551
The interaction of Brooker’s merocyanine (BM), a merocyanine dye, with calix[4]pyrrole (CP) was studied in acetonitrile. BM is violet in solution, but its interaction with CP changes the color of the solution due to the formation of CP-BM species associated through hydrogen bonding. A displacement assay was then carried out in the presence of different anions (F−, Cl−, Br−, I−, , , and ). It was verified that F−, and to a lesser extent Cl− and , displace BM through the formation of a complex with CP, coloring the solution. Addition of makes the solution almost colorless because it is sufficiently acidic to transfer a proton to BM, removing it from the receptor site in CP and protonating the dye, thereby allowing the visual detection of the anion in relation to the other anions. 相似文献
92.
Maya Neytcheva Erik B?ngtsson Elisabeth Linn��r 《Advances in Computational Mathematics》2011,35(2-4):323-355
In this work we analyse a method to construct numerically efficient and computationally cheap sparse approximations of some of the matrix blocks arising in the block-factorized preconditioners for matrices with a two-by-two block structure. The matrices arise from finite element discretizations of partial differential equations. We consider scalar elliptic problems, however the approach is appropriate also for other types of problems such as parabolic problems or systems of equations. The technique is applicable for both selfadjoint and non-selfadjoint problems, in two as well as in three space dimensions. We analyse in detail the two-dimensional case and provide extensive numerical evidence for the efficiency of the proposed matrix approximations, both serial and parallel. Two- and three-dimensional tests are included. 相似文献
93.
Carsten Kügeler Roland Rosezin Eike Linn Rainer Bruchhaus Rainer Waser 《Applied Physics A: Materials Science & Processing》2011,102(4):791-809
The paper reports on the characterization of bipolar resistive switching materials and their integration into nanocrossbar
structures, as well as on different memory operation schemes in terms of memory density and the challenging problem of sneak
paths. TiO2, WO3, GeSe, SiO2 and MSQ thin films were integrated into nanojunctions of 100×100 nm2. The variation between inert Pt and Cu or Ag top electrodes leads to valence change (VCM) switching or electrochemical metallization
(ECM) switching and has significant impact on the resistive properties. All materials showed promising characteristics with
switching speeds down to 10 ns, multilevel switching, good endurance and retention. Nanoimprint lithography was found to be
a suitable tool for processing crossbar arrays down to a feature size of 50 nm and 3D stacking was demonstrated. The inherent
occurrence of current sneak paths in passive crossbar arrays can be circumvented by the implementation of complementary resistive
switching (CRS) cells. The comparison with other operation schemes shows that the CRS concept dramatically increases the addressable
memory size to about 1010 bit. 相似文献
94.
Rozenshtein V Wagnert L Berg A Stavitski E Berthold T Kothe G Saltsman I Gross Z Levanon H 《The journal of physical chemistry. A》2008,112(24):5338-5343
The photoexcited states of two 5,10,15-tris(pentafluorophenyl)corroles (tpfc), hosting Rh(III) in their core, namely Rh(pyr)(PPh 3)(tpfc) and Rh(PPh 3)(tpfc), have been studied by time-resolved electron paramagnetic resonance (TREPR) combined with pulsed laser excitation. Using the transient nutation technique, the spin polarized spectra are assigned to photoexcited triplet states. The spectral widths observed for the two Rh(III) corroles crucially depend on the axial ligands at the Rh(III) metal ion. In case of Rh(PPh 3)(tpfc), the TREPR spectra are found to extend over 200 mT, which exceeds the spectral width of non-transition-metal corroles by more than a factor of 3. Moreover, the EPR lines of the Rh(III) corroles are less symmetric than those of the non-transition-metal corrroles. The peculiarities in the TREPR spectra of the Rh(III) corroles can be rationalized in terms of strong spin-orbit coupling (SOC) associated with the transition-metal character of the Rh(III) ion. It is assumed that SOC in the photoexcited Rh(III) corroles effectively admixes metal centered (3)dd-states to the corrole centered (3)pipi*-states detected in the TREPR experiments. This admixture leads to an increased zero-field splitting and a large g-tensor anisotropy as manifested by the excited Rh(III) corroles. 相似文献