全文获取类型
收费全文 | 1315篇 |
免费 | 32篇 |
国内免费 | 4篇 |
专业分类
化学 | 792篇 |
晶体学 | 7篇 |
力学 | 83篇 |
数学 | 117篇 |
物理学 | 352篇 |
出版年
2022年 | 9篇 |
2021年 | 15篇 |
2020年 | 26篇 |
2019年 | 17篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 32篇 |
2015年 | 21篇 |
2014年 | 17篇 |
2013年 | 45篇 |
2012年 | 57篇 |
2011年 | 72篇 |
2010年 | 34篇 |
2009年 | 41篇 |
2008年 | 62篇 |
2007年 | 58篇 |
2006年 | 48篇 |
2005年 | 46篇 |
2004年 | 47篇 |
2003年 | 32篇 |
2002年 | 27篇 |
2001年 | 22篇 |
2000年 | 24篇 |
1999年 | 17篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 26篇 |
1995年 | 15篇 |
1994年 | 16篇 |
1993年 | 21篇 |
1992年 | 22篇 |
1991年 | 41篇 |
1990年 | 20篇 |
1989年 | 22篇 |
1988年 | 21篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 22篇 |
1984年 | 26篇 |
1983年 | 25篇 |
1982年 | 21篇 |
1981年 | 13篇 |
1980年 | 21篇 |
1979年 | 10篇 |
1978年 | 24篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1975年 | 13篇 |
1972年 | 8篇 |
1968年 | 8篇 |
排序方式: 共有1351条查询结果,搜索用时 62 毫秒
61.
62.
Ross S. Winter Dr. Jun Yan Dr. Christoph Busche Dr. Jennifer S. Mathieson Dr. Alessandro Prescimone Prof. Euan K. Brechin Dr. De‐Liang Long Prof. Leroy Cronin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(9):2976-2981
Two near isomeric clusters containing a novel {Mn8W4} Keggin cluster within a [W36Mn10Si4O136(OH)4(H2O)8]24? cluster are reported: K10Li14 [W36Si4O136MnII10(OH)4(H2O)8] ( 1 ) and K10Li13.5Mn0.25[W36Si4O136MnII10(OH)4(H2O)8] ( 1′ ). Bulk characterization of the clusters has been carried out by single crystal X‐ray structure analysis, ICP‐MS, TGA, ESI‐MS, CV and SQUID‐magnetometer analysis. X‐ray analysis revealed that 1′ has eight positions within the central Keggin core that were disordered W/Mn whereas 1 contained no such disorder. This subtle difference is due to a differences is how the two clusters assemble and recrystallize from the same mother liquor and represents a new type of isomerism. The rapid recrystallization process was captured via digital microscopy and this uncovered two “intermediate” types of crystal which formed temporarily and provided nucleation sites for the final clusters to assemble. The intermediates were investigated by single crystal X‐ray analysis and revealed to be novel clusters K4Li22[W36Si4Mn7O136(H2O)8]?56 H2O ( 2 ) and Mn2K8Li14[W36Si4Mn7O136(H2O)8]?45 H2O ( 3 ). The intermediate clusters contained different yet related building blocks to the final clusters which allowed for the postulation of a mechanism of assembly. This demonstrates a rare example where the use X‐ray crystallography directly facilitated understanding the means by which a POM assembled. 相似文献
63.
We study Minkowski contents and fractal curvatures of arbitrary self-similar tilings (constructed on a feasible open set of an IFS) and the general relations to the corresponding functionals for self-similar sets. In particular, we characterize the situation, when these functionals coincide. In this case, the Minkowski content and the fractal curvatures of a self-similar set can be expressed completely in terms of the volume function or curvature data, respectively, of the generator of the tiling. In special cases such formulas have been obtained recently using tube formulas and complex dimensions or as a corollary to results on self-conformal sets. Our approach based on the classical Renewal Theorem is simpler and works for a much larger class of self-similar sets and tilings. In fact, generator type formulas are obtained for essentially all self-similar sets, when suitable volume functions (and curvature functions, respectively) related to the generator are used. We also strengthen known results on the Minkowski measurability of self-similar sets, in particular on the question of non-measurability in the lattice case. 相似文献
64.
Zamira Fetahaj Dr. Michel W. Jaworek Dr. Rosario Oliva Prof. Dr. Roland Winter 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(48):e202201658
The high colloidal stability of antibody (immunoglobulin) solutions is important for pharmaceutical applications. Inert cosolutes, excipients, are generally used in therapeutic protein formulations to minimize physical instabilities, such as liquid–liquid phase separation (LLPS), aggregation and precipitation, which are often encountered during manufacturing and storage. Despite their widespread use, a detailed understanding of how excipients modulate the specific protein-protein interactions responsible for these instabilities is still lacking. In this work, we demonstrate the high sensitivity to pressure of globulin condensates as a suitable means to suppress LLPS and subsequent aggregation of concentrated antibody solutions. The addition of excipients has only a minor effect. The high pressure sensitivity observed is due to the fact that these flexible Y-shaped molecules create a considerable amount of void volume in the condensed phase, leading to an overall decrease in the volume of the system upon dissociation of the droplet phase by pressure already at a few tens of to hundred bar. Moreover, we show that immunoglobulin molecules themselves are highly resistant to unfolding under pressure, and can even sustain pressures up to about 6 kbar without conformational changes. This implies that immunoglobulins are resistant to the pressure treatment of foods, such as milk, in high-pressure food-processing technologies, thereby preserving their immunological activity. 相似文献
65.
Christoph Peschel Stefan van Wickeren Yves Preibisch Verena Naber Denis Werner Lars Frankenstein Dr. Fabian Horsthemke Prof. Dr. Urs Peuker Prof. Dr. Martin Winter Dr. Sascha Nowak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(22):e202200485
Herein we report on an analytical study of dry-shredded lithium-ion battery (LIB) materials with unknown composition. Samples from an industrial recycling process were analyzed concerning the elemental composition and (organic) compound speciation. Deep understanding of the base material for LIB recycling was obtained by identification and analysis of transition metal stoichiometry, current collector metals, base electrolyte and electrolyte additive residues, aging marker molecules and polymer binder fingerprints. For reversed engineering purposes, the main electrode and electrolyte chemistries were traced back to pristine materials. Furthermore, possible lifetime application and accompanied aging was evaluated based on target analysis on characteristic molecules described in literature. With this, the reported analytics provided precious information for value estimation of the undefined spent batteries and enabled tailored recycling process deliberations. The comprehensive feedstock characterization shown in this work paves the way for targeted process control in LIB recycling processes. 相似文献
66.
Andreev VA Banks TI Case TA Chitwood DB Clayton SM Crowe KM Deutsch J Egger J Freedman SJ Ganzha VA Gorringe T Gray FE Hertzog DW Hildebrandt M Kammel P Kiburg B Knaack S Kravtsov PA Krivshich AG Lauss B Lynch KL Maev EM Maev OE Mulhauser F Ozben CS Petitjean C Petrov GE Prieels R Schapkin GN Semenchuk GG Soroka MA Tishchenko V Vasilyev AA Vorobyov AA Vznuzdaev ME Winter P;MuCap Collaboration 《Physical review letters》2007,99(3):032002
The rate of nuclear muon capture by the proton has been measured using a new technique based on a time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas, which is key to avoiding uncertainties from muonic molecule formation. The capture rate from the hyperfine singlet ground state of the microp atom was obtained from the difference between the micro(-) disappearance rate in hydrogen and the world average for the micro(+) decay rate, yielding Lambda(S)=725.0+/-17.4 s(-1), from which the induced pseudoscalar coupling of the nucleon, g(P)(q(2)=-0.88m(2)(micro))=7.3+/-1.1, is extracted. 相似文献
67.
We address the problem of "nonlocal computation," in which separated parties must compute a function without any individual learning anything about the inputs. Surprisingly, entanglement provides no benefit over local classical strategies for such tasks, yet stronger nonlocal correlations allow perfect success. This provides intriguing insights into the limits of quantum information processing, the nature of quantum nonlocality, and the differences between quantum and stronger-than-quantum nonlocal correlations. 相似文献
68.
Parmish Kaur Lukas Mai Arbresha Muriqi David Zanders Ramin Ghiyasi Dr. Muhammad Safdar Nils Boysen Manuela Winter Prof. Michael Nolan Prof. Maarit Karppinen Prof. Anjana Devi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(15):4913-4926
Owing to the limited availability of suitable precursors for vapor phase deposition of rare-earth containing thin-film materials, new or improved precursors are sought after. In this study, we explored new precursors for atomic layer deposition (ALD) of cerium (Ce) and ytterbium (Yb) containing thin films. A series of homoleptic tris-guanidinate and tris-amidinate complexes of cerium (Ce) and ytterbium (Yb) were synthesized and thoroughly characterized. The C-substituents on the N-C-N backbone (Me, NMe2, NEt2, where Me=methyl, Et=ethyl) and the N-substituents from symmetrical iso-propyl (iPr) to asymmetrical tertiary-butyl (tBu) and Et were systematically varied to study the influence of the substituents on the physicochemical properties of the resulting compounds. Single crystal structures of [Ce(dpdmg)3] 1 and [Yb(dpdmg)3] 6 (dpdmg=N,N'-diisopropyl-2-dimethylamido-guanidinate) highlight a monomeric nature in the solid-state with a distorted trigonal prismatic geometry. The thermogravimetric analysis shows that the complexes are volatile and emphasize that increasing asymmetry in the complexes lowers their melting points while reducing their thermal stability. Density functional theory (DFT) was used to study the reactivity of amidinates and guanidinates of Ce and Yb complexes towards oxygen (O2) and water (H2O). Signified by the DFT calculations, the guanidinates show an increased reactivity toward water compared to the amidinate complexes. Furthermore, the Ce complexes are more reactive compared to the Yb complexes, indicating even a reactivity towards oxygen potentially exploitable for ALD purposes. As a representative precursor, the highly reactive [Ce(dpdmg)3] 1 was used for proof-of-principle ALD depositions of CeO2 thin films using water as co-reactant. The self-limited ALD growth process could be confirmed at 160 °C with polycrystalline cubic CeO2 films formed on Si(100) substrates. This study confirms that moving towards nitrogen-coordinated rare-earth complexes bearing the guanidinate and amidinate ligands can indeed be very appealing in terms of new precursors for ALD of rare earth based materials. 相似文献
69.
70.
Dr. Andreas Lerchen Dr. Narasimhulu Gandhamsetty Elliot H. E. Farrar Dr. Nils Winter Dr. Johannes Platzek Dr. Matthew N. Grayson Prof. Dr. Varinder K. Aggarwal 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23307-23311
(−)-Finerenone is a nonsteroidal mineralocorticoid receptor antagonist currently in phase III clinical trials for the treatment of chronic kidney disease in type 2 diabetes. It contains an unusual dihydronaphthyridine core. We report a 6-step synthesis of (−)-finerenone, which features an enantioselective partial transfer hydrogenation of a naphthyridine using a chiral phosphoric acid catalyst with a Hantzsch ester. The process is complicated by the fact that the naphthyridine exists as a mixture of two atropisomers that react at different rates and with different selectivities. The intrinsic kinetic resolution was converted into a kinetic dynamic resolution at elevated temperature, which enabled us to obtain (−)-finerenone in both high yield and high enantioselectivity. DFT calculations have revealed the origin of selectivity. 相似文献