全文获取类型
收费全文 | 2007篇 |
免费 | 58篇 |
国内免费 | 12篇 |
专业分类
化学 | 1269篇 |
晶体学 | 20篇 |
力学 | 89篇 |
数学 | 245篇 |
物理学 | 454篇 |
出版年
2023年 | 11篇 |
2021年 | 20篇 |
2020年 | 34篇 |
2019年 | 18篇 |
2018年 | 14篇 |
2016年 | 31篇 |
2015年 | 22篇 |
2014年 | 34篇 |
2013年 | 87篇 |
2012年 | 89篇 |
2011年 | 118篇 |
2010年 | 45篇 |
2009年 | 48篇 |
2008年 | 106篇 |
2007年 | 96篇 |
2006年 | 90篇 |
2005年 | 92篇 |
2004年 | 83篇 |
2003年 | 76篇 |
2002年 | 57篇 |
2001年 | 57篇 |
2000年 | 61篇 |
1999年 | 33篇 |
1998年 | 17篇 |
1997年 | 18篇 |
1996年 | 35篇 |
1995年 | 30篇 |
1994年 | 32篇 |
1993年 | 25篇 |
1992年 | 33篇 |
1991年 | 28篇 |
1990年 | 32篇 |
1989年 | 34篇 |
1988年 | 27篇 |
1987年 | 11篇 |
1986年 | 18篇 |
1985年 | 34篇 |
1984年 | 27篇 |
1983年 | 26篇 |
1982年 | 23篇 |
1981年 | 14篇 |
1980年 | 19篇 |
1979年 | 21篇 |
1978年 | 24篇 |
1977年 | 30篇 |
1976年 | 20篇 |
1975年 | 17篇 |
1974年 | 20篇 |
1973年 | 17篇 |
1972年 | 17篇 |
排序方式: 共有2077条查询结果,搜索用时 15 毫秒
1.
Elisa Martinelli Elisa Guazzelli Cristina Bartoli Matteo Gazzarri Federica Chiellini Giancarlo Galli Maureen E. Callow James A. Callow John A. Finlay Sophie Hill 《Journal of polymer science. Part A, Polymer chemistry》2015,53(10):1213-1225
Well‐defined amphiphilic pentablock copolymers Siy‐(EGx‐FAz)2 composed of polysiloxane (Si), polyethylene glycol (EG), and perfluorohexylethyl polyacrylate (FA) blocks are synthesized by ATRP of FA monomer starting from a difunctional bromo‐terminated macroinitiator. Diblock copolymers EGx‐FAz are also synthesized as model systems. The block copolymers are used, either alone or blended with a PDMS matrix in varied loadings, to prepare antibiofouling coatings. Angle‐resolved XPS and contact angle measurements show that the coating surface is highly enriched in fluorine content but undergoes reconstruction after contact with water. Protein adsorption experiments with human serum albumin and calf serum highlight that diblock copolymers resist protein adhesion better than do pentablock copolymers. Blending of the pentablock copolymer with PDMS results in increased protein adsorption. By contrast, the PDMS‐matrix coatings show high removal percentages of sporelings of the green fouling alga Ulva linza. © 2015 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 2015 , 53, 1213–1225 相似文献
2.
Chris H. Hill Agnete H. Viuff Samantha J. Spratley Stéphane Salamone Stig H. Christensen Randy J. Read Nigel W. Moriarty Henrik H. Jensen Janet E. Deane 《Chemical science》2015,6(5):3075-3086
Krabbe disease is a devastating neurodegenerative disorder characterized by rapid demyelination of nerve fibers. This disease is caused by defects in the lysosomal enzyme β-galactocerebrosidase (GALC), which hydrolyzes the terminal galactose from glycosphingolipids. These lipids are essential components of eukaryotic cell membranes: substrates of GALC include galactocerebroside, the primary lipid component of myelin, and psychosine, a cytotoxic metabolite. Mutations of GALC that cause misfolding of the protein may be responsive to pharmacological chaperone therapy (PCT), whereby small molecules are used to stabilize these mutant proteins, thus correcting trafficking defects and increasing residual catabolic activity in cells. Here we describe a new approach for the synthesis of galacto-configured azasugars and the characterization of their interaction with GALC using biophysical, biochemical and crystallographic methods. We identify that the global stabilization of GALC conferred by azasugar derivatives, measured by fluorescence-based thermal shift assays, is directly related to their binding affinity, measured by enzyme inhibition. X-ray crystal structures of these molecules bound in the GALC active site reveal which residues participate in stabilizing interactions, show how potency is achieved and illustrate the penalties of aza/iminosugar ring distortion. The structure–activity relationships described here identify the key physical properties required of pharmacological chaperones for Krabbe disease and highlight the potential of azasugars as stabilizing agents for future enzyme replacement therapies. This work lays the foundation for new drug-based treatments of Krabbe disease. 相似文献
3.
Courtney Ngai Colomba M. Sanchez-Marsetti Prof. Dr. W. Hill Harman Prof. Richard J. Hooley 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(52):23711-23715
An endohedrally functionalized self-assembled Fe4L6 cage complex can catalyze oxa-Pictet—Spengler cyclizations of tryptophols and various aldehyde derivatives, showing strong rate accelerations and size-selectivity. Selective molecular recognition of substrates controls the reactivity, and the cage is capable of binding and activating multiple different species along the multistep reaction pathway. The combination of a functionalized active site, size-selective reactivity, and multistep activation, all from a single host molecule, illustrates the biomimetic nature of the catalysis. 相似文献
4.
5.
Grace C. Thaggard Dr. Gabrielle A. Leith Daniil Sosnin Dr. Corey R. Martin Kyoung Chul Park Margaret K. McBride Dr. Jaewoong Lim Brandon J. Yarbrough Buddhima K. P. Maldeni Kankanamalage Gina R. Wilson Austin R. Hill Dr. Mark D. Smith Prof. Dr. Sophya Garashchuk Prof. Dr. Andrew B. Greytak Prof. Dr. Ivan Aprahamian Prof. Dr. Natalia B. Shustova 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202211776
Confinement-imposed photophysics was probed for novel stimuli-responsive hydrazone-based compounds demonstrating a conceptual difference in their behavior within 2D versus 3D porous matrices for the first time. The challenges associated with photoswitch isomerization arising from host interactions with photochromic compounds in 2D scaffolds could be overcome in 3D materials. Solution-like photoisomerization rate constants were realized for sterically demanding hydrazone derivatives in the solid state through their coordinative immobilization in 3D scaffolds. According to steady-state and time-resolved photophysical measurements and theoretical modeling, this approach provides access to hydrazone-based materials with fast photoisomerization kinetics in the solid state. Fast isomerization of integrated hydrazone derivatives allows for probing and tailoring resonance energy transfer (ET) processes as a function of excitation wavelength, providing a novel pathway for ET modulation. 相似文献
6.
Miharu Eguchi Minsu Han Yusuke Asakura Jonathan P. Hill Joel Henzie Katsuhiko Ariga Alan E. Rowan Watcharop Chaikittisilp Yusuke Yamauchi 《Angewandte Chemie (International ed. in English)》2023,62(46):e202307615
Reactions occurring at surfaces and interfaces necessitate the creation of well-designed surface and interfacial structures. To achieve a combination of bulk material (i.e., framework) and void spaces, a meticulous process of “nano-architecting” of the available space is necessary. Conventional porous materials such as mesoporous silica, zeolites, and metal–organic frameworks lack advanced cooperative functionalities owing to their largely monotonous pore geometries and limited conductivities. To overcome these limitations and develop functional structures with surface-specific functions, the novel materials space-tectonics methodology has been proposed for future materials synthesis. This review summarizes recent examples of materials synthesis based on designing building blocks (i.e., tectons) and their hybridization, along with practical guidelines for implementing materials syntheses and state-of-the-art examples of practical applications. Lastly, the potential integration of materials space-tectonics with emerging technologies, such as materials informatics, is discussed. 相似文献
7.
Sara M. Rodriguez Ysidro N. Motta Michael R. Hill Laura M. Oelke Carly C. Carter Thomas R. Cundari Muhammed Yousufuddin 《Acta Crystallographica. Section C, Structural Chemistry》2023,79(4):158-163
An asymmetric bis(silyl) niobocene hydride complex, namely, bis(η5-cyclopentadienyl)(fluorodimethylsilyl)hydrido(iododimethylsilyl)niobium, [Nb(C5H5)2(C2H6FSi)(C2H6ISi)H] or Cp2NbH(SiIMe2)(SiFMe2), has been studied to determine the effect of the silyl ligand on the position of the hydride attached to the Nb atom. It has been shown that when a Group 17 atom is substituted onto one of the silyl ligands, there is a greater interaction between the hydride and this ligand, as demonstrated by a shorter Si…H distance. In the present work, we have investigated the effect when the silyl ligands are substituted by different Group 17 atoms. We present here the structure and DFT calculations of Cp2NbH(SiIMe2)(SiFMe2), showing that the position of the hydride is located between the two silyl ligands. The results from our investigation show that the hydride is closer to the silyl ligand that is substituted by fluorine. 相似文献
8.
Bryan S. Holtzman Eric T. Roberts Nicholas S. Caminiti Jacob A. Fox Madison B. Goodstein Staci A. Hill Zitong B. Jia Isabelle N.-M. Leibler Michael L. Martini Gina M. Mendolia Sarah B. Nodder Molly S. Costanza-Robinson Richard C. Bunt 《Tetrahedron letters》2017,58(5):432-436
A nucleophile crossover experiment was used to monitor the reversibility of nucleophilic addition of benzylamine to π-allylpalladium complexes. Dppe, dppp, dppb, and PHOX showed more crossover than PPh3 and dppm in both DMF and dichloromethane. Crossover was inhibited by the addition of DBU or Cs2CO3, but much less elimination to diene side products was observed with Cs2CO3. Analysis of percent crossover vs. percent reaction completion using the PHOX ligand revealed that with added DBU or Cs2CO3 crossover only began occurring after 100% completion had been reached. 相似文献
9.
Six controllable states are known to exist for all homogeneous, isotropic, incompressible, elastic bodies. It is shown that certain pairs of these controllable states may be superposed in Mooney-Rivlin materials thereby constructing new controllable states for these materials.
This work was carried out while both authors were associated with the Department of Aerospace Engineering and Engineering Mechanics at The University of Texas at Austin and was supported by U.S. National Science Foundation Grant GK-37367 to that institution. 相似文献
Zusammenfassung Es gibt sechs kontrollierbare Zustände für alle homogenen, isotropischen, inkompressiblen, elastischen Körper. Es ist gezeigt dass gewisse Paare dieser kontrollierbaren Zustände geschichtet werden können in Mooney-Rivlin Materialen und dadurch neue kontrollierbare Zustände für diese Materialen geschaffen werden.
This work was carried out while both authors were associated with the Department of Aerospace Engineering and Engineering Mechanics at The University of Texas at Austin and was supported by U.S. National Science Foundation Grant GK-37367 to that institution. 相似文献
10.
The effect of a crack on the bending and shearing of an anisotropic elastic slab is considered. The problems considered are reduced to simultaneous Fredholm equations which may be solved numerically. 相似文献