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101.
102.
Amido analogs of geldanamycin, an ansamycin anticancer agent, were designed, synthesized, and assayed with SKBR3 cells, in which stability of HER2 receptor tyrosine kinase is dependent on the chaperone Hsp90. An amide was employed as a trisubstituted alkene isostere at the C8,9 position, which provided for a simplified, convergent synthesis through two major fragments, an aniline-amine left-hand portion and a dicarboxylic acid right-hand piece. 相似文献
103.
Jeong‐il Park Shoshannah L. Roth Kristin E. Price D. Tyler McQuade 《Journal of polymer science. Part A, Polymer chemistry》2006,44(10):3271-3278
We demonstrate that conformational‐biased monomers can alter neighboring monomer conformation leading to globe changes in polymer topology. This work is compared to the “sergeants and soldiers” effect observed when a small percentage of optically active monomers control a polymer's helical handedness. Specifically, we show that one biased monomer in a sequence of flexible monomers yields an oligonucleotide block copolymer that folds into two topologies with competitive free energies and activation barriers (from an unfolded state). Double substitutions, on the other hand, have varying degrees of influence depending on the position of the second substitution. Substitutions within the same guanosine block have a lesser effect relative to substitutions in different blocks. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3271–3278, 2006 相似文献
104.
Abdrrahman S. Surur Kristin Beirow Christian Bock Lukas Schulig Dr. Markus K. Kindermann Dr. Anja Bodtke Prof. Dr. Werner Siegmund Prof. Dr. Patrick J. Bednarski Prof. Dr. Andreas Link 《ChemistryOpen》2019,8(1):41-44
Neuronal voltage-gated potassium channels KV7.2/KV7.3 are sensitive to small-molecule drugs such as flupirtine, even though physiological response occurs in the absence of ligands. Clinically, prolonged use of flupirtine as a pain medication is associated with rare cases of drug-induced liver injury. Thus, safety concerns prevent a broader use of this non-opioid and non-steroidal analgesic in therapeutic areas with unmet medical needs such as hyperactive bladder or neonatal seizures. With the goal of studying influences of chemical structure on activity and toxicity of flupirtine, we explored modifications of the benzylamino bridge and the substitution pattern in both rings of flupirtine. Among twelve derivatives, four novel thioether derivatives showed the desired activity in cellular assays and may serve as leads for safer KV channel openers. 相似文献
105.
106.
Martin Scherer Karl Fischer Frank Depoix Thomas Fritz Raphael Thiermann Kristin Mohr Rudolf Zentel 《Macromolecular rapid communications》2016,37(1):60-66
In this work, activated ester chemistry is employed to synthesize biocompatible and readily functionalizable polymersomes. Via aminolysis of pentafluorophenyl methacrylate‐based precursor polymers, an N‐(2‐hydroxypropyl) methacrylamide (HPMA)‐analog hydrophilic block is obtained. The precursor polymers can be versatile functionalized by simple addition of suitable primary amines during aminolysis as demonstrated using a fluorescent dye. Vesicle formation is proven by cryoTEM and light scattering. High encapsulation efficiencies for hydrophilic cargo like siRNA are achieved using dual centrifugation and safe encapsulation is demonstrated by gel electrophoresis. In vitro studies reveal low cytotoxicity and no protein adsorption‐induced aggregation in human blood serum occurs, making the vesicles interesting candidates as nanosized drug carriers.
107.
Huan Peng Kristin Rübsam Felix Jakob Patrizia Pazdzior Ulrich Schwaneberg Andrij Pich 《Macromolecular rapid communications》2016,37(21):1765-1771
Novel redox‐responsive polymeric nanogels that allow highly efficient enzyme encapsulation and reversible modulation of enzyme activity are developed. The nanogel synthesis and encapsulation of enzyme are performed simultaneously via in situ crosslinking of pyridyldisulfide‐functionalized water‐soluble reactive copolymers, which are synthesized via reversible addition–fragmentation chain transfer copolymerization. Obtained nanogels with loaded cellulase demonstrate very good colloidal stability in aqueous solutions. The enzymatic activity of cellulase is greatly reduced when encapsulated in the nanogels and rapidly recovered in 10 × 10−3 m dithiothreitol solution. Fluorescence resonance energy transfer (FRET)‐based experiments indicate that the recovered enzymatic activity is mainly ascribed to the release of the enzyme due to the degradation of the disulfide crosslinking network after addition of dithiothreitol (DTT), instead of the enhanced substrate transport rate. The developed enzyme immobilization method opens new possibilities for reversible activation/deactivation of enzymes and opens up new directions for targeted protein therapy and biotechnology applications.
108.
Benjamin W. Gung Prof. Dr. Derek T. Craft Lauren N. Bailey Kristin Kirschbaum Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(2):639-644
Macrocyclic propargyl acetates containing a furan ring were prepared by using a CrCl2‐promoted reaction. In the presence of either a AuI or AuIII catalyst, a tandem 3,3‐rearrangement/transannular [4+3] cycloaddition reaction occurred to give propargyl acetates that are regio‐ and diastereospecific. The regiochemistry of the product is controlled by the position of the acetoxy group in the starting material and the stereochemistry of the reaction depends on the ring size. 相似文献
109.
Jeffrey M. McMahon Anne-Isabelle Henry Kristin L. Wustholz Michael J. Natan R. Griffith Freeman Richard P. Van Duyne George C. Schatz 《Analytical and bioanalytical chemistry》2009,394(7):1819-1825
Finite element method calculations were carried out to determine extinction spectra and the electromagnetic (EM) contributions
to surface-enhanced Raman spectroscopy (SERS) for 90-nm Au nanoparticle dimers modeled after experimental nanotags. The calculations
revealed that the EM properties depend significantly on the junction region, specifically the distance between the nanoparticles
for spacings of less than 1 nm. For extinction spectra, spacings below 1 nm lead to maxima that are strongly red-shifted from
the 600-nm plasmon maximum associated with an isolated nanoparticle. This result agrees qualitatively well with experimental
transmission electron microscopy images and localized surface plasmon resonance spectra that are also presented. The calculations
further revealed that spacings below 0.5 nm, and especially a slight fusing of the nanoparticles to give tiny crevices, leads
to EM enhancements of 1010 or greater. Assuming a uniform coating of SERS molecules around both nanoparticles, we determined that regardless of the
separation, the highest EM fields always dominate the SERS signal. In addition, we determined that for small separations less
than 3% of the molecules always contribute to greater than 90% of the signal.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
110.
Let L be a totally real field of strict class number one and let OL be its ring of integers. Let p be a rational prime which is unramified in L. We consider the distance between two superspecial abelian varieties with real multiplication in characteristic p, where by “distance” we mean the minimal degree of an OL-isogeny. We give upper and lower bounds on the distance between superspecial abelian varieties with real multiplication by L in characteristic p in terms of p and the degree and discriminant of L. 相似文献