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991.
Claudio Monasterolo Ryan O'Gara Saranna E. Kavanagh Sadbh E. Byrne Bartosz Bieszczad Orla Murray Michael Wiesinger Rebecca A. Lynch Kirill Nikitin Declan G. Gilheany 《Chemical science》2022,13(21):6262
A new class of biaryl chiral ligands derived from 1,2-diaminocyclohexane (1,2-DACH) has been designed to enable the asymmetric addition of aliphatic and, for the first time, aromatic Grignard reagents to ketones for the preparation of highly enantioenriched tertiary alcohols (up to 95% ee). The newly developed ligands L12 and L12′ together with the previously reported L0 and L0′ define a set of complementary chiral promoters, which provides access to the modular construction of a broad range of structurally diverse non-racemic tertiary alcohols, bearing challenging quaternary stereocenters. The present advancements bring to completion our asymmetric Grignard methodology by expanding the scope to aromatic organomagnesium reagents, while facilitating its implementation in organic synthesis thanks to improved synthetic routes for the straightforward access to the chiral ligands. The synthetic utility of the method has been demonstrated by the development of a novel and highly enantioselective formal synthesis of the antihistamine API clemastine via intermediate (R)-3a. Exploiting the power of the 3-disconnection approach offered by the Grignard synthesis, (R)-3a is obtained in 94% ee with ligand (R,R)-L12. The work described herein marks the finalization of our ongoing effort towards the establishment of an effective and broadly applicable methodology for the asymmetric Grignard synthesis of chiral tertiary alcohols.Easily applied enantioselective addition of aliphatic and aromatic Grignard reagents to ketones provides modular and universal access to challenging chiral tertiary alcohols, enabling the straightforward preparation of natural products and APIs. 相似文献
992.
Since the nuclei in a molecule are treated as stationary, it is perhaps natural that interpretations of molecular properties and reactivity have focused primarily upon the electronic density distribution. The role of the nuclei has generally received little explicit consideration. Our objective has been to at least partially redress this imbalance in emphasis. We discuss a number of examples in which the nuclei play the determining role with respect to molecular properties and reactive behavior. It follows that conventional interpretations based solely upon electronic densities and donating or withdrawing tendencies should be made with caution. 相似文献
993.
Christopher S. Wilson Dr. Timothy J. Prior Dr. Jordon Sandland Huguette Savoie Prof. Ross W. Boyle Dr. Benjamin S. Murray 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(50):11593-11603
Dinuclear metallodrugs offer much potential in the development of novel anticancer chemotherapeutics as a result of the distinct interactions possible with bio-macromolecular targets and the unique biological activity that can result. Herein, we describe the development of isostructural homo-dinuclear OsII–OsII and hetero-dinuclear OsII–RuII organometallic complexes formed from linking the arene ligands of [M(η6-arene)(C2O4)(PTA)] units (M=Os/Ru; PTA=1,3,5-triaza-7-phosphaadamantane). Using these complexes together with the known RuII–RuII analogue, a chromatin-modifying agent, we probed the impact of varying the metal ions on the structure, reactivity and biological activity of these complexes. The complexes were structurally characterised by X-ray diffraction experiments, their stability and reactivity were examined by using 1H and 31P NMR spectroscopy, and their biological activity was assessed, alongside that of mononuclear analogues, through MTT assays and cell-cycle analysis (HT-29 cell line). The results revealed high antiproliferative activity in each case, with cell-cycle profiles of the dinuclear complexes found to be similar to that for untreated cells, and similar but distinct profiles for the mononuclear complexes. These results indicate these complexes impact on cell viability predominantly through a non-DNA-damaging mechanism of action. The new OsII–OsII and OsII–RuII complexes reported here are further examples of a family of compounds operating via mechanisms of action atypical of the majority of metallodrugs, and which have potential as tools in chromatin research. 相似文献
994.
Dr. Neshat Rozatian Dr. Antal Harsanyi Ben J. Murray Alexander S. Hampton Emily J. Chin Alexander S. Cook Dr. David R. W. Hodgson Prof. Graham Sandford 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(52):12027-12035
Fluorinated steroids, which are synthesised by electrophilic fluorination, form a significant proportion of marketed pharmaceuticals. To gain quantitative information on fluorination at the 6-position of steroids, kinetics studies were conducted on enol ester derivatives of progesterone, testosterone, cholestenone and hydrocortisone with a series of electrophilic N−F reagents. The stereoselectivities of fluorination reactions of progesterone enol acetate and the kinetic effects of additives, including methanol and water, were investigated. The kinetics of epimerisation of 6β-fluoroprogesterone to the more pharmacologically active 6α-fluoroprogesterone isomer in HCl/acetic acid solutions are detailed. 相似文献
995.
Angelo Frei Johannes Zuegg Alysha G. Elliott Murray Baker Stefan Braese Christopher Brown Feng Chen Christopher G. Dowson Gilles Dujardin Nicole Jung A. Paden King Ahmed M. Mansour Massimiliano Massi John Moat Heba A. Mohamed Anna K. Renfrew Peter J. Rutledge Peter J. Sadler Matthew H. Todd Charlotte E. Willans Justin J. Wilson Matthew A. Cooper Mark A. T. Blaskovich 《Chemical science》2020,11(17):4531
996.
Freideriki Michailidou Tomas Lebl Alexandra M. Z. Slawin Sunil Vishnuprasadji Sharma Murray J. B. Brown Rebecca Jane Miriam Goss 《Molecules (Basel, Switzerland)》2020,25(23)
Fluorinated nucleoside analogues have attracted much attention as anticancer and antiviral agents and as probes for enzymatic function. However, the lack of direct synthetic methods, especially for 2′,3′-dideoxy-2′,3′-difluoro nucleosides, hamper their practical utility. In order to design more efficient synthetic methods, a better understanding of the conformation and mechanism of formation of these molecules is important. Herein, we report the synthesis and conformational analysis of a 2′,3′-dideoxy-2′,3′-difluoro and a 2′-deoxy-2′-fluoro uridine derivative and provide an insight into the reaction mechanism. We suggest that the transformation most likely diverges from the SN1 or SN2 pathway, but instead operates via a neighbouring-group participation mechanism. 相似文献
997.
Vicky V. T. Doan‐Nguyen Patrick J. Carroll Christopher B. Murray 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(3):239-241
Trioctylphosphine oxide (TOPO), C24H51OP, was recrystallized from ambient evaporation in acetone. TOPO single crystals form with a monoclinic P21/c structure. Fourier transform IR (FT–IR) spectroscopy captures the characteristic stretching modes from the seven methylene groups, the phosphoryl P=O bond, and the phosphoryl–carbon bond. 相似文献
998.
Digital imaging is used to study the particle positions and trajectories of a layer of highly charged 0.3 μm diameter polystyrene spheres in water suspension, rigidly confined into two-dimensions between two smooth glass plates. As the in-plane sphere density is varied, we find a two-stage melting transition in which we observe separate divergences in the orientational and translational order at different densities, separated by roughly 4%. The topological defect statistics are complex, but qualitatively consistent with the predictions of Halperin and Nelson. 相似文献
999.
1000.
Katherine B. Szpakolski Kay Latham Dr. Colin J. Rix Jonathan M. White Prof. Boujemaa Moubaraki Dr. Keith S. Murray Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(5):1691-1696
The synthesis and crystal structure elucidation of a novel dinuclear heteroleptic copper(II) complex has led to an alternative mechanism in the formation of covalent hydrates. During further studies on the synthesis and properties of [Cu2(ophen)2] ( 1 ), a dinuclear complex of copper(I) with 1 H‐[1,10]‐phenanthrolin‐2‐one (Hophen), two intermediates/alternative products 2 and 3 were isolated. The dinuclear, antiferromagnetic complex [Cu2(ophen)2(phen)2] ? (NO3)2 ? 9H2O ( 3 , phen=1,10‐phenanthroline) contains two five‐coordinate copper(II) ions, both with trigonal‐bipyramidal coordination, which are bridged together through deprotonated hydroxyl groups with a Cu? Cu non‐bonding distance of 3.100 Å. Complex [Cu(phen)2(H2O)] ? (NO3)2 ( 2 ) is a polymorph of a previously reported material. The occurrence of 2 and 3 has led us to propose a variation to the Gillard mechanism for the formation of covalent hydrates in bidentate N‐heterocycles in which the attacking nucleophile may be the deprotonated form of 2 , [Cu(phen)2(OH)]?, rather than free OH?. 相似文献