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71.
Willans CE Sinenkov MA Fukin GK Sheridan K Lynam JM Trifonov AA Kerton FM 《Dalton transactions (Cambridge, England : 2003)》2008,(27):3592-3598
Reaction of two equivalents of n-BuLi with sterically demanding amine-bis(phenol) compounds, H(2)O(2)NN'(R) (Me(2)NCH(2)CH(2)N{CH(2)-3,5-R(2)-C(6)H(2)OH}(2); R = t-Bu or t-Pe (tert-pentyl)) yields isolable lithium complexes, Li(2)(O(2)NN'(R)), in good yields. Upon reaction with one equivalent of LnCl(3)(THF)(x), the lithium salts afford rare earth amine-phenolate chloride complexes in good yields, Ln(O(2)NN'(R))Cl(THF); Ln = Y, Yb, Ho, Gd, Sm, Pr. Crystals of Y(O(2)NN'(t-Bu))Cl(THF), 1, and Sm(O(2)NN'(t-Bu))Cl(DME), 2, suitable for single crystal X-ray crystallographic analysis were obtained. In contrast to previously reported [{Gd(O(2)NN'(t-Pe))(THF)(micro-Cl)}(2)] and related La and Sm complexes, these species are monomeric. 1 contains Y in a distorted octahedral environment bonded to two amine, two phenolate, one THF and one chloride donor. 2 contains Sm in a distorted capped trigonal prismatic environment bonded to two amine, two phenolate, two DME oxygens and one chloride donor. The Ln(O(2)NN'(t-Pe))Cl(THF) complexes were active initators for the controlled ring-opening polymerization of epsilon-caprolactone with a tendency to form low molecular weight cyclic polyesters (M(n) 3000-5000). The conversion rates, although slower than related amido and alkyl species, were different for monomeric and dimeric initiators. The size of the metal centre also affected the conversions and the molecular weights achieved. 相似文献
72.
Niklas Jänsch Wisely Oki Sugiarto Marius Muth Aleksandra Kopranovic Charlotte Desczyk Matthias Ballweg Frank Kirschhöfer Dr. Gerald Brenner-Weiss Prof. Dr. Franz-Josef Meyer-Almes 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(58):13249-13255
Human histone deacetylase 8 is a well-recognized target for T-cell lymphoma and particularly childhood neuroblastoma. PD-404,182 was shown to be a selective covalent inhibitor of HDAC8 that forms mixed disulfides with several cysteine residues and is also able to transform thiol groups to thiocyanates. Moreover, HDAC8 was shown to be regulated by a redox switch based on the reversible formation of a disulfide bond between cysteines Cys102 and Cys153. This study on the distinct effects of PD-404,182 on HDAC8 reveals that this compound induces the dose-dependent formation of intramolecular disulfide bridges. Therefore, the inhibition mechanism of HDAC8 by PD-404,182 involves both, covalent modification of thiols as well as ligand mediated disulfide formation. Moreover, this study provides a deep molecular insight into the regulation mechanism of HDAC8 involving several cysteines with graduated capability to form reversible disulfide bridges. 相似文献
73.
Dr. Jagadeesh Yerri Dr. José Dias Dr. Mallikajurna Reddy Nimmakayala Franck Razafindrainibe Charlotte Courageux Anne-Julie Gastellier Johanne Jegoux Dr. Caroline Coisne Dr. Christophe Landry Dr. Fabien Gosselet Johan Hachani Dr. Jean-François Goossens Prof. Marie-Pierre Dehouck Dr. Florian Nachon Dr. Rachid Baati 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(65):15035-15044
Novel 6-alkyl- and 6-alkenyl-3-fluoro-2-pyridinaldoximes have been synthesised by using a mild and efficient chemoselective hydrogenation of 6-alkynyl-3-fluoro-2-pyridinaldoxime scaffolds, without altering the reducible, unprotected, sensitive oxime functionality and the C−F bond. These novel 6-alkyl-3-fluoro-2-pyridinaldoximes may find medicinal application as antidotes to organophosphate poisoning. Indeed, one low-molecular-weight compound exhibited increased affinity for sarin-inhibited acetylcholinesterase (hAChE) and greater reactivation efficiency or resurrection for sarin-inhibited hAChE, compared with those of 2-pyridinaldoxime (2-PAM) and 1-({[4-(aminocarbonyl)pyridinio]methoxy}methyl)-2-[(hydroxyimino)methyl]pyridinium chloride (HI-6), two pyridinium salts currently used as antidote by several countries. In addition, the uncharged 3-fluorinated bifunctional hybrid showed increased in vitro blood–brain barrier permeability compared with those of 2-PAM, HI-6 and obidoxime. These promising features of novel low-molecular-weight alkylfluoropyridinaldoxime open up a new era for the design, synthesis and discovery of central non-quaternary broad spectrum reactivators for organophosphate-inhibited cholinesterases. 相似文献
74.
Charlotte Menager Nathanaël Guigo Luc Vincent Nicolas Sbirrazzuoli 《Journal of polymer science. Part A, Polymer chemistry》2020,58(12):1717-1727
The curing of epoxidized linseed oil (ELO) with three different bio-based dicarboxylic acids (sebacic acid, suberic acid, and succinic acid) has been investigated. No accelerators or catalysts were used and the resulting thermosets are 100% bio-based. Structural investigations of the three crosslinked ELO resins were made using FTIR spectroscopy and TMA, that is, tensile tests, TGA, and DMA. As evidenced by FTIR measurements ELO and dicarboxylic acids reacts but no major differences can be distinguished between the dicarboxylic acids. Non-isothermal curing has been conducted by rheological and DSC measurements. Advanced isoconversional analysis applied to DSC data in association with the complex viscosity variations gives new insights into the polymerization mechanism. The length of dicarboxylic acid carbon chain modifies the reaction rate. Then, a correlation between reaction rate, activation energy, pre-exponential factors, polymerization mechanism, and change in rate-limiting step was shown. DMA and tensile tests highlight the relationship between the carbon chain length, reactivity, and thermomechanical properties. The use of succinic acid allows reaching a higher Tg and thermal stability. 相似文献
75.
Maria Weber Hai-Hao Han Bo-Han Li Maria
L. Odyniec Charlotte E. F. Jarman Yi Zang Steven D. Bull Amanda B. Mackenzie Adam C. Sedgwick Jia Li Xiao-Peng He Tony D. James 《Chemical science》2020,11(32):8567
Reaction-based fluorescent-probes have proven successful for the visualisation of biological species in various cellular processes. Unfortunately, in order to tailor the design of a fluorescent probe to a specific application (i.e. organelle targeting, material and theranostic applications) often requires extensive synthetic efforts and the synthetic screening of a range of fluorophores to match the required synthetic needs. In this work, we have identified Pinkment-OH as a unique “plug-and-play” synthetic platform that can be used to develop a range of ONOO− responsive fluorescent probes for a variety of applications. These include theranostic-based applications and potential material-based/bioconjugation applications. The as prepared probes displayed an excellent sensitivity and selectivity for ONOO− over other ROS. In vitro studies using HeLa cells and RAW 264.7 macrophages demonstrated their ability to detect exogenously and endogenously produced ONOO−. Evaluation in an LPS-induced inflammation mouse model illustrated the ability to monitor ONOO− production in acute inflammation. Lastly, theranostic-based probes enabled the simultaneous evaluation of indomethacin-based therapeutic effects combined with the visualisation of an inflammation biomarker in RAW 264.7 cells. Pinkment, a resorufin based ONOO− selective and sensitive ‘plug and play’ fluorescence-based platform for in vitro and in vivo use, enables facile functionalisation for various imaging and theranostic applications. 相似文献
76.
Kätchen K. Lachmayr Charlotte M. Wentz Prof. Lawrence R. Sita 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1537-1542
“One-component” soft material Frank–Kasper (FK) phases are an intriguing structural form of matter that possess periodically ordered structures arising from the self-reconfiguration and close packing of an initial assembly of identical “deformable” spheres into two or more size- or shape-distinct sets of particles. Significant challenges that must still be addressed to advance the field of soft matter FK phases further, however, include their rare and unpredictable occurrence, uncertain mechanisms of solid-state assembly, and low thermodynamic stability. Here we show that a readily-accessible sugar–polyolefin conjugate quantitatively produces an exceptionally stable solid-state FK A15 phase through a rapid and irreversible thermotropic order–order transition, which contrary to other prevailing proposed mechanisms, does not require mass transfer between particles or large structural reorganization in the bulk to establish unit cell non-equivalency. Our results provide the basis for a realistic strategy for obtaining practical and scalable quantities of a diverse range of sugar–polyolefin FK A15 phases with unique intrinsic physical properties and chemical reactivities not previously seen in such systems. 相似文献
77.
Murray V. Baker David H. Brown Peter V. Simpson Brian W. Skelton Allan H. White Charlotte C. Williams 《Journal of organometallic chemistry》2006,691(26):5845-5855
New Pd(II), Pt(II) and Rh(I) N-heterocyclic carbene (NHC) complexes containing two NHC units linked by an ortho-xylyl group are described and structurally and spectroscopically characterised. The Pt(II) complexes represent the first examples of Pt-bis(NHC) complexes where the NHC units are linked by an ortho-xylyl group. Functionalisation of the bis(NHC) ligands with heptyl groups has been used as a means of enhancing the solubility of the complexes, in order to facilitate spectroscopic characterisation and catalytic studies. The catalytic activity of the palladium(II) complexes in Heck and Suzuki cross-coupling reactions has been examined to investigate any effects of the diverse structural changes, though these appear to be insignificant. 相似文献
78.
Taylor TJ Burress CN Pandey L Gabbaï FP 《Dalton transactions (Cambridge, England : 2003)》2006,(39):4654-4656
Both pentafluorophenylmercury chloride and trimeric perfluoro-ortho-phenylene mercury interact with phenanthrene to form phosphorescent adducts which exhibit extended binary stacks in the solid state. 相似文献
79.
Møller C Sprenger RR Stürup S Højrup P 《Analytical and bioanalytical chemistry》2011,401(5):1623-1633
Using insulin as a model protein for binding of oxaliplatin to proteins, various mass spectrometric approaches and techniques
were compared. Several different platinum adducts were observed, e.g. addition of one or two diaminocyclohexane platinum(II)
(Pt(dach)) molecules. By top-down analysis and fragmentation of the intact insulin–oxaliplatin adduct using nano-electrospray
ionisation quadrupole time-of-flight mass spectrometry (nESI-Q-ToF-MS), the major binding site was assigned to histidine5
on the insulin B chain. In order to simplify the interpretation of the mass spectrum, the disulphide bridges were reduced.
This led to the additional identification of cysteine6 on the A chain as a binding site along with histidine5 on the B chain.
Digestion of insulin–oxaliplatin with endoproteinase Glu-C (GluC) followed by reduction led to the formation of five peptides
with Pt(dach) attached. Identification of several of the binding sites was obtained using matrix-assisted laser desorption/ionization
(MALDI)-ToF-ToF-MS and liquid chromatography-nESI-Q-ToF-MS. Upon comparing the top-down and bottom-up approaches, the suitability
of the bottom-up approach for determining binding sites was questioned, as the release and possible re-association of Pt(dach)
were demonstrated upon enzymatic digestion. The associated advantages and disadvantages of ESI and MALDI were also pointed
out. 相似文献
80.
Charlotte James Thomas Pugh Andrew L. Johnson A. Tobias A. Jenkins 《European Polymer Journal》2011,(6):1338-1345
A system for incorporating antimicrobial zinc into polymeric materials, in particular hydrogel type polymers has been developed. Zn(Bipy-(MMOES)2) a zinc carboxylate monomer was designed with the purpose of mimicking commercial cross linking agents such as ethylene glycol diacrylate, as well as containing antimicrobial zinc ions (Zn2+), with the intention that it can be used to cross link into any polymeric material, the example here being polyacrylic acid. Two systems were studied: a homopolymer of the Zn(Bipy-(MMOES)2) and copolymers of Zn(Bipy-(MMOES)2) with acrylic acid (AA). The AA – Zn(Bipy-(MMOES)2) produced water swellable polymers which retained antimicrobial activity. The ability of the polymers to release the zinc ions was shown to be pH responsive and the leachate analysed to give a proposed mechanism of action. The Zn(Bipy-(MMOES)2) monomer and polymers have shown antibacterial activity against both gram positive Methicillin susceptible staphylococcus aureus (MSSA 476) and gram negative Pseudomonas aeruginosa (PA01). 相似文献