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91.
A new series of 1,3‐Benzoxazines were synthesized from ketimines and triphosgene. The synthesized compounds were characterized by IR, 1HNMR, and mass spectral data. The synthesized compounds on bioevaluation indicated significant antifungal activity. 相似文献
92.
Biocatalytic Synthesis of Allylic and Allenyl Sulfides through a Myoglobin‐Catalyzed Doyle–Kirmse Reaction
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Dr. Vikas Tyagi Dr. Gopeekrishnan Sreenilayam Dr. Priyanka Bajaj Antonio Tinoco Prof. Dr. Rudi Fasan 《Angewandte Chemie (International ed. in English)》2016,55(43):13562-13566
The first example of a biocatalytic [2,3]‐sigmatropic rearrangement reaction involving allylic sulfides and diazo reagents (Doyle–Kirmse reaction) is reported. Engineered variants of sperm whale myoglobin catalyze this synthetically valuable C?C bond‐forming transformation with high efficiency and product conversions across a variety of sulfide substrates (e.g., aryl‐, benzyl‐, and alkyl‐substituted allylic sulfides) and α‐diazo esters. Moreover, the scope of this myoglobin‐mediated transformation could be extended to the conversion of propargylic sulfides to give substituted allenes. Active‐site mutations proved effective in enhancing the catalytic efficiency of the hemoprotein in these reactions as well as modulating the enantioselectivity, resulting in the identification of the myoglobin variant Mb(L29S,H64V,V68F), which is capable of mediating asymmetric Doyle–Kirmse reactions with an enantiomeric excess up to 71 %. This work extends the toolbox of currently available biocatalytic strategies for the asymmetric formation of carbon–carbon bonds. 相似文献
93.
Kaliyaperumal Thanigaimani Nuridayanti Che Khalib Suhana Arshad Madhukar Hemamalini 《Molecular Crystals and Liquid Crystals》2016,625(1):259-275
The 1:1 cocrystal of 2-amino-3-bromopyridine (2A3BP) with 4-methylbenzoic acid (4MBA) has been prepared by slow evaporation method in methanol, which was crystallized in monoclinic P21/c space group having two molecules in the asymmetric unit. The cocrystal has been characterized by single crystal X-ray analysis, FTIR, 1H NMR, 13C NMR, and Powder XRD. Theoretical investigations have been calculated by HF and density function (B3LYP) method with the 6-311+G(d,p) basis set. The vibrational frequencies together with the 1H NMR and 13C NMR chemical shifts have been calculated on the fully optimized geometry of 1. Theoretical calculations of bond parameters, harmonic vibration frequencies, and isotropic chemical shifts are in good agreement with the experimental results. Solvent-free formation of these cocrystal was confirmed by powder X-ray diffraction analysis. The crystal structure was stabilized by Npyridine—H···O = C, C = O—H···Npyridine and C—H···Br hydrogen bonding interactions. 相似文献
94.
Madhukar S. Chande Pravin A. Barve Vijay Suryanarayan 《Journal of heterocyclic chemistry》2007,44(1):49-53
95.
Madhukar N. Jachak Dhananjay B. Kendre A. B. Avhale Raghunath B. Toche Ram W. Sabnis 《Journal of heterocyclic chemistry》2007,44(6):1525-1528
96.
Photoinduced electron transfer in a hexaphenylbenzene-based self-assembled porphyrin-fullerene triad
Terazono Y Kodis G Liddell PA Garg V Gervaldo M Moore TA Moore AL Gust D 《Photochemistry and photobiology》2007,83(2):464-469
A hexaphenylbenzene-based zinc porphyrin dyad forms a 1:1 complex with a fullerene bearing two pyridyl groups via coordination of the pyridyl nitrogens with the zinc atoms. The fullerene is symmetrically located between the two zinc porphyrins. The binding constant for the complex is 7.3 x 10(4) M(-1) in 1,2-difluorobenzene. Photoinduced electron transfer from a porphyrin first excited singlet state to the fullerene occurs with a time constant of 3 ps, and the resulting charge-separated state has a lifetime of 230 ps. This self-assembled construct should form a basis for the construction of more elaborate model photosynthetic antenna-reaction center systems. 相似文献
97.
Madhukar N. Jachak Sandeep M. Bagul Bhausaheb K. Ghotekar Raghunath B. Toche 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):655-662
Abstract A series of (2E)-3-(1-chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-1-(4-aryl)prop-2-en-1-ones (chalcones) have been synthesized by a new
synthetic route. The 3-pyridinecarbonitrile derivatives were synthesized by the Michael reaction of malononitrile (in base)
and aroylacetonitriles (in acid) with chalcones in one pot. The fluorescent properties and quantum yields of these compounds
were studied.
Graphical Abstract
相似文献
98.
Madhukar N. Jachak Sandeep M. Bagul Bhausaheb K. Ghotekar Raghunath B. Toche 《Monatshefte für Chemie / Chemical Monthly》2009,20(5):655-662
Abstract
A series of (2E)-3-(1-chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-1-(4-aryl)prop-2-en-1-ones (chalcones) have been synthesized by a new synthetic route. The 3-pyridinecarbonitrile derivatives were synthesized by the Michael reaction of malononitrile (in base) and aroylacetonitriles (in acid) with chalcones in one pot. The fluorescent properties and quantum yields of these compounds were studied. 相似文献99.
Tatko CD Nanda V Lear JD Degrado WF 《Journal of the American Chemical Society》2006,128(13):4170-4171
Polar interactions have a profound influence on membrane stability and structure. A membrane-solubilized GCN4 peptide, MS-1, is used to study the impact of polar networks. Amide functionalities from amino acid side chains have been shown to promote peptide oligomerization, but lacked specificity. Herein, the hydrogen bonding interactions of an Asn side chain are coupled with the hydroxyl of Ser or Thr to generate a polar network. Analytical ultracentrifugation and fluorescence resonance energy transfer studies indicate that a trimer assembly is established where each membrane-embedded hydrogen bond contributes 1 kcal mol-1. 相似文献
100.
Polypeptides incorporating D-amino acids occasionally occur in nature and are an important class of pharmaceutical molecules. With the use of heterochiral Monte Carlo (HCMC), a method inspired by the de novo design of proteins, we develop peptide scaffolds for interacting with a molecular target, a left-handed alpha-helix. The HCMC approach concurrently seeks to optimize a peptide sequence, its internal conformation, and its docked conformation with a target surface. Several major classes of interactions are observed: (1) homochiral interactions between two alphaL helices, (2) heterochiral interactions between an alphaL and an alphaR helix, and (3) heterochiral interactions between the alphaL target and novel nonhelical structures. We explore the application of HCMC to simulating the preferential enantioselectivity of heterochiral complexes. Implications for biomimetic design in molecular recognition are discussed. 相似文献