全文获取类型
收费全文 | 14025篇 |
免费 | 666篇 |
国内免费 | 98篇 |
专业分类
化学 | 9811篇 |
晶体学 | 75篇 |
力学 | 234篇 |
数学 | 2134篇 |
物理学 | 2535篇 |
出版年
2023年 | 106篇 |
2022年 | 90篇 |
2021年 | 185篇 |
2020年 | 349篇 |
2019年 | 307篇 |
2018年 | 192篇 |
2017年 | 157篇 |
2016年 | 490篇 |
2015年 | 377篇 |
2014年 | 447篇 |
2013年 | 748篇 |
2012年 | 909篇 |
2011年 | 1081篇 |
2010年 | 592篇 |
2009年 | 465篇 |
2008年 | 858篇 |
2007年 | 857篇 |
2006年 | 837篇 |
2005年 | 783篇 |
2004年 | 581篇 |
2003年 | 417篇 |
2002年 | 391篇 |
2001年 | 143篇 |
2000年 | 125篇 |
1999年 | 101篇 |
1998年 | 104篇 |
1997年 | 144篇 |
1996年 | 171篇 |
1995年 | 151篇 |
1994年 | 173篇 |
1993年 | 157篇 |
1992年 | 137篇 |
1991年 | 115篇 |
1990年 | 96篇 |
1989年 | 85篇 |
1988年 | 66篇 |
1987年 | 74篇 |
1985年 | 122篇 |
1984年 | 103篇 |
1983年 | 75篇 |
1982年 | 118篇 |
1981年 | 96篇 |
1980年 | 83篇 |
1979年 | 109篇 |
1978年 | 95篇 |
1977年 | 88篇 |
1976年 | 97篇 |
1975年 | 67篇 |
1974年 | 63篇 |
1973年 | 89篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Dr. Deepak Gupta Dr. Alae E. Lakraychi Dr. Buddha D. Boruah Simon De Kreijger Dr. Ludovic Troian-Gautier Prof. Benjamin Elias Prof. Michael De Volder Prof. Alexandru Vlad 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(42):e202201220
Controlling redox activity of judiciously appended redox units on a photo-sensitive molecular core is an effective strategy for visible light energy harvesting and storage. The first example of a photosensitizer - electron donor coordination compound in which the photoinduced electron transfer step is used for light to electrical energy conversion and storage is reported. A photo-responsive Ru-diimine module conjugated with redox-active catechol groups in [Ru(II)(phenanthroline-5,6-diolate)3]4− photosensitizer can mediate photoinduced catechol to dione oxidation in the presence of a sacrificial electron acceptor or at the surface of an electrode. Under potentiostatic condition, visible light triggered current density enhancement confirmed the light harvesting ability of this photosensitizer. Upon implementation in galvanostatic charge-discharge of a Li battery configuration, the storage capacity was found to be increased by 100 %, under 470 nm illumination with output power of 4.0 mW/cm−2. This proof-of-concept molecular system marks an important milestone towards a new generation of molecular photo-rechargeable materials. 相似文献
2.
Archiv der Mathematik - Motivated by recent results on the minimal base of a permutation group, we introduce a new local invariant attached to arbitrary finite groups. More precisely, a subset... 相似文献
3.
Gabrielle A. Leith Allison M. Rice Brandon J. Yarbrough Anna A. Berseneva Richard T. Ly Charles N. Buck III Dr. Denis Chusov Amy J. Brandt Prof. Dr. Donna A. Chen Benjamin W. Lamm Prof. Dr. Morgan Stefik Kenneth S. Stephenson Dr. Mark D. Smith Prof. Dr. Aaron K. Vannucci Dr. Perry J. Pellechia Prof. Dr. Sophya Garashchuk Prof. Dr. Natalia B. Shustova 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(15):6056-6062
The effect of donor (D)–acceptor (A) alignment on the materials electronic structure was probed for the first time using novel purely organic porous crystalline materials with covalently bound two- and three-dimensional acceptors. The first studies towards estimation of charge transfer rates as a function of acceptor stacking are in line with the experimentally observed drastic, eight-fold conductivity enhancement. The first evaluation of redox behavior of buckyball- or tetracyanoquinodimethane-integrated crystalline was conducted. In parallel with tailoring the D-A alignment responsible for “static” changes in materials properties, an external stimulus was applied for “dynamic” control of the electronic profiles. Overall, the presented D–A strategic design, with stimuli-controlled electronic behavior, redox activity, and modularity could be used as a blueprint for the development of electroactive and conductive multidimensional and multifunctional crystalline porous materials. 相似文献
4.
Laurens Kooijman Dr. Matthias Schuster Christian Baumann Simon Jurt Dr. Frank Löhr Dr. Boris Fürtig Prof. Dr. Peter Güntert Prof. Dr. Oliver Zerbe 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21151-21158
To achieve efficient proton pumping in the light-driven proton pump bacteriorhodopsin (bR), the protein must be tightly coupled to the retinal to rapidly convert retinal isomerization into protein structural rearrangements. Methyl group dynamics of bR embedded in lipid nanodiscs were determined in the dark-adapted state, and were found to be mostly well ordered at the cytosolic side. Methyl groups in the M145A mutant of bR, which displays only 10 % residual proton pumping activity, are less well ordered, suggesting a link between side-chain dynamics on the cytosolic side of the bR cavity and proton pumping activity. In addition, slow conformational exchange, attributed to low frequency motions of aromatic rings, was indirectly observed for residues on the extracellular side of the bR cavity. This may be related to reorganization of the water network. These observations provide a detailed picture of previously undescribed equilibrium dynamics on different time scales for ground-state bR. 相似文献
5.
6.
Ein elektronenreiches cyclisches (Alkyl)(amino)carben auf Au(111)-, Ag(111)- und Cu(111)-Oberflächen
Anne Bakker Dr. Matthias Freitag Elena Kolodzeiski Peter Bellotti Dr. Alexander Timmer Dr. Jindong Ren Bertram Schulze Lammers Daniel Moock Prof. Dr. Herbert W. Roesky Dr. Harry Mönig Dr. Saeed Amirjalayer Prof. Dr. Harald Fuchs Prof. Dr. Frank Glorius 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13745-13749
7.
Journal of Statistical Physics - We consider the symmetric exclusion process on suitable random grids that approximate a compact Riemannian manifold. We prove that a class of random walks on these... 相似文献
8.
9.
10.
Unusual Bonding and Properties in Main Group Element Chemistry: Rational Synthesis,Characterization, and Experimental Electron Density Determination of Mixed‐Valent Tetraphosphetes 下载免费PDF全文
Verena Breuers Prof. Dr. Christian W. Lehmann Prof. Dr. Walter Frank 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4596-4606
Five dispirocyclic λ3,λ5‐tetraphosphetes [{R2Si(NR1)(NR2)P2}2] (R1 = R2 and R1 ≠ R2) are easily prepared in almost quantitative yields via photolysis of the respective bis(trimethylsilyl)phosphanyldiazaphosphasiletidines with intense visible light. These deep‐yellow low‐coordinate phosphorus compounds can be considered as the first higher congeners of the well‐known cyclodiphosphazenes. The tetraphosphetes are remarkably stable in air and show unexpected molecular properties related to the unique bonding situation of the central four‐π‐electron four‐membered phosphorus ring. The extent of rhombic distortion of the central P4 ring is remarkable due to an unusually acute angle at the σ2‐phosphorus atoms. All of the P?P bonds are approximately equal in length. The distances are in the middle of the range given by phosphorus single and double bonds. The anisotropic absorption of visible light that can easily be observed in the case of the yellow/colorless dichroic crystals of [{Me2Si(NtBu)(NtBu)P2}2] and the exceptional 31P NMR chemical shift of the σ2‐phosphorus atoms are the most remarkable features of the λ3,λ5‐tetraphosphetes. In the case of [{Me2Si(NtBu)(NtBu)P2}2], the Hansen–Coppens multipole model is applied to extract the electron density from high‐resolution X‐ray diffraction data obtained at 100 K. Static deformation density and topological analysis reveal a unique bonding situation in the central unsaturated P4 fragment characterized by polar σ‐bonding, pronounced out‐of‐ring non‐bonding lone pair density on the σ2‐phosphorus atoms, and an additional non‐classical three‐center back‐bonding contribution. 相似文献