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101.
MnO2‐Modified Persistent Luminescence Nanoparticles for Detection and Imaging of Glutathione in Living Cells and In Vivo 下载免费PDF全文
Dr. Na Li Wei Diao Yaoyao Han Dr. Wei Pan Tingting Zhang Prof. Bo Tang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16488-16491
Persistent luminescence nanoparticles (PLNPs) hold great promise for the detection and imaging of biomolecules. Herein, we have demonstrated a novel nanoprobe, based on the manganese dioxide (MnO2)‐modified PLNPs, that can detect and image glutathione in living cells and in vivo. The persistent luminescence of the PLNPs can be efficiently quenched by the MnO2 nanosheets. In the presence of glutathione (GSH), MnO2 was reduced to Mn2+ and the luminescence of PLNPs can be restored. The persistent luminescence property can allow detection and imaging without external excitation and avoid the background noise originating from the in situ excitation. This strategy can offer a promising platform for detection and imaging of reactive species in living cells or in vivo. 相似文献
102.
Dramatic Influence of an Anionic Donor on the Oxygen‐Atom Transfer Reactivity of a MnV–Oxo Complex 下载免费PDF全文
Heather M. Neu Dr. Matthew G. Quesne Tzuhsiung Yang Dr. Katharine A. Prokop‐Prigge Prof. Kyle M. Lancaster James Donohoe Prof. Serena DeBeer Dr. Sam P. de Visser Prof. David P. Goldberg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(45):14584-14588
Addition of an anionic donor to an MnV(O) porphyrinoid complex causes a dramatic increase in 2‐electron oxygen‐atom‐transfer (OAT) chemistry. The 6‐coordinate [MnV(O)(TBP8Cz)(CN)]? was generated from addition of Bu4N+CN? to the 5‐coordinate MnV(O) precursor. The cyanide‐ligated complex was characterized for the first time by Mn K‐edge X‐ray absorption spectroscopy (XAS) and gives Mn?O=1.53 Å, Mn?CN=2.21 Å. In combination with computational studies these distances were shown to correlate with a singlet ground state. Reaction of the CN? complex with thioethers results in OAT to give the corresponding sulfoxide and a 2e?‐reduced MnIII(CN)? complex. Kinetic measurements reveal a dramatic rate enhancement for OAT of approximately 24 000‐fold versus the same reaction for the parent 5‐coordinate complex. An Eyring analysis gives ΔH≠=14 kcal mol?1, ΔS≠=?10 cal mol?1 K?1. Computational studies fully support the structures, spin states, and relative reactivity of the 5‐ and 6‐coordinate MnV(O) complexes. 相似文献
103.
Combining Complementary Ligands into one Framework for the Construction of a Ferromagnetically Coupled [MnIII12] Wheel 下载免费PDF全文
Dr. Sergio Sanz Jamie M. Frost Thayalan Rajeshkumar Dr. Scott J. Dalgarno Dr. Gopalan Rajaraman Dr. Wolfgang Wernsdorfer Prof. Jürgen Schnack Dr. Paul. J. Lusby Prof. Euan K. Brechin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):3010-3013
Phenolic oxime and diethanolamine moieties have been combined into one organic framework, resulting in the formation of a novel ligand type that can be employed to construct a rare and unusual dodecametallic Mn wheel, within which nearest neighbours are coupled ferromagnetically. 相似文献
104.
Manganese‐Corrole Complexes as Versatile Catalysts for the Ring‐Opening Homo‐ and Co‐Polymerization of Epoxide 下载免费PDF全文
Dr. Carine Robert Takahiro Ohkawara Prof. Dr. Kyoko Nozaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(16):4789-4795
Manganese‐corrole complexes in combination with a co‐catalyst [PPN]X ([PPN]+=bis(triphenylphosphoranylidene)iminium) were found to be new versatile catalysts for the polymerization of epoxides, copolymerization of epoxides with CO2, and copolymerization of epoxides with cyclic anhydrides affording a wide range of polymeric materials. This work should allow the synthesis of new types of improved innovative (co)polymers with original properties and would clearly increase the number of applications for polyesters, polycarbonates, and polyethers. 相似文献
105.
Dr. Jiang Zhu Dr. Eric M. Gale Dr. Iliyana Atanasova Dr. Tyson A. Rietz Dr. Peter Caravan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(44):14507-14513
A MnII chelating dendrimer was prepared as a contrast agent for MRI applications. The dendrimer comprises six tyrosine‐derived [Mn(EDTA)(H2O)]2? moieties coupled to a cyclotriphosphazene core. Variable temperature 17O NMR spectroscopy revealed a single water co‐ligand per MnII that undergoes fast water exchange (kex=(3.0±0.1)×108 s?1 at 37 °C). The 37 °C per MnII relaxivity ranged from 8.2 to 3.8 mM ?1 s?1 from 0.47 to 11.7 T, and is sixfold higher on a per molecule basis. From this field dependence a rotational correlation time was estimated as 0.45(±0.02) ns. The imaging and pharmacokinetic properties of the dendrimer were compared to clinically used [Gd(DTPA)(H2O)]2? in mice at 4.7 T. On first pass, the higher per ion relaxivity of the dendrimer resulted in twofold greater blood signal than for [Gd(DTPA)(H2O)]2?. Blood clearance was fast and elimination occurred through both the renal and hepatobiliary routes. This MnII containing dendrimer represents a potential alternative to Gd‐based contrast agents, especially in patients with chronic kidney disease where the use of current Gd‐based agents may be contraindicated. 相似文献
106.
Insertion of a Single‐Molecule Magnet inside a Ferromagnetic Lattice Based on a 3D Bimetallic Oxalate Network: Towards Molecular Analogues of Permanent Magnets 下载免费PDF全文
Dr. Miguel Clemente‐León Prof. Eugenio Coronado Prof. Carlos J. Gómez‐García Dr. Maurici López‐Jordà Dr. Agustín Camón Ana Repollés Dr. Fernando Luis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(6):1669-1676
The insertion of the single‐molecule magnet (SMM) [MnIII(salen)(H2O)]22+ (salen2?=N,N′‐ethylenebis‐(salicylideneiminate)) into a ferromagnetic bimetallic oxalate network affords the hybrid compound [MnIII(salen)(H2O)]2[MnIICrIII(ox)3]2 ? (CH3OH) ? (CH3CN)2 ( 1 ). This cationic Mn2 cluster templates the growth of crystals formed by an unusual achiral 3D oxalate network. The magnetic properties of this hybrid magnet are compared with those of the analogous compounds [MnIII(salen)(H2O)]2[ZnIICrIII(ox)3]2 ? (CH3OH) ? (CH3CN)2 ( 2 ) and [InIII(sal2‐trien)][MnIICrIII(ox)3] ? (H2O)0.25 ? (CH3OH)0.25 ? (CH3CN)0.25 ( 3 ), which are used as reference compounds. In 2 it has been shown that the magnetic isolation of the Mn2 clusters provided by their insertion into a paramagnetic oxalate network of CrIII affords a SMM behavior, albeit with blocking temperatures well below 500 mK even for frequencies as high as 160 kHz. In 3 the onset of ferromagnetism in the bimetallic MnIICrIII network is observed at Tc=5 K. Finally, in the hybrid compound 1 the interaction between the two magnetic networks leads to the antiparallel arrangement of their respective magnetizations, that is, to a ferrimagnetic phase. This coupling induces also important changes on the magnetic properties of 1 with respect to those of the reference compounds 2 and 3 . In particular, compound 1 shows a large magnetization hysteresis below 1 K, which is in sharp contrast with the near‐reversible magnetizations that the SMMs and the oxalate ferromagnetic lattice show under the same conditions. 相似文献
107.
Cover Picture: Insertion of a Single‐Molecule Magnet inside a Ferromagnetic Lattice Based on a 3D Bimetallic Oxalate Network: Towards Molecular Analogues of Permanent Magnets (Chem. Eur. J. 6/2014) 下载免费PDF全文
108.
Hélène Bordeneuve Sophie Guillemet-Fritsch Sophie Schuurman 《Journal of solid state chemistry》2009,182(2):396-401
Cobalt manganese oxide spinels Mn3−xCoxO4 (with 0.98?x?3) were prepared by the thermal decomposition in air of oxalate precursors. The influence of the thermal treatments on the structure of these materials is emphasized. Single-phase ceramics were obtained after optimization of the sintering parameters. A precise phase diagram for the Co-Mn-O system is proposed according to thermal stability and structure of oxide powders. The electrical measurements on single-phase ceramics show that low values of resistivity can be achieved. The conduction could take place through jumps of polarons between Mn3+ and Mn4+ on octahedral sites. These compounds present interesting electrical characteristics for negative temperature coefficient (NTC) thermistor applications. 相似文献
109.
Ramaswamy Murugavel Prof. Subramaniam Kuppuswamy Nayanmoni Gogoi Alexander Steiner Dr. John Bacsa Dr. Ramamoorthy Boomishankar Dr. K. G. Suresh Prof. 《化学:亚洲杂志》2009,4(1):143-153
Tetranuclear manganese(II) phosphates [Mn(dipp)(bpy)]4?4 H2O ( 1 ) and [Mn4(dmpp)2(dmppH)4(bpy)4(H2O)2]?H2O ( 2 ) have been prepared from Mn(OAc)2?4 H2O and 2,6‐diisopropylphenyl phosphate (dippH2) or 2,6‐dimethylphenyl phosphate (dmppH2) in the presence of 2,2′‐bipyridine (bpy). In contrast, the reaction between [Mn(bpy)2(OAc)(ClO4)]?H2O and dippH2 affords [Mn(bpy)2(dippH)]2?2 ClO4?2 CH3OH ( 3 ). The reactions of Mn(OAc)2?4 H2O, dippH2, and pyridine (py) or 3,5‐dimethylpyrazole (dmpz) in CH3CN under reflux afford hexanuclear complexes [Mn6(dipp)6(py)8]?2CH3CN ( 4 ) and [Mn6(dipp)6(dmpz)6(AcOH)2]?2 H2O ( 5 ), respectively. Although compounds 1 and 2 are tetrameric, the former is a closed cubane‐like structure resembling the D4R secondary building unit of zeolites, whereas the latter exists in a staircase structure with fused Mn2O4P2 rings. The core structure of 3 contains a Mn2O4P2 eight‐membered ring that resembles the S4R building block of zeolites. Single‐crystal X‐ray diffraction studies reveal that compounds 4 and 5 have a similar core structure and differ from each other by the neutral ligands coordinated to manganese ions. All six phosphate ligands exist in a doubly deprotonated [(RO)PO32?] form and exhibit two types of binding modes [5.222] and [3.111]. An interesting feature of compounds 1 – 5 is that although they are oligonuclear complexes, there is an absence of oxido bridges. The magnetic properties of compounds 1 – 5 have been investigated in the temperature range 5–298 K, and it was found that all the compounds obey the Curie law. 相似文献
110.
A new metal-organic complex [Mn2(PDC)2(bipy)2(H2O)2] (H2PDC = 2,4-pyridine-dicarboxylic acid, bipy = 2,2′-bipyridine) 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG and single-crystal X-ray diffraction. The compound crystallizes in triclinic, space group P ^-1 with a = 7.376(3), b = 9.990(4), c = 11.950(5) A^°, α= 75.217(5), β = 78.052(5), γ = 70.655(5)°, V = 796.0(5)A^°3, C34HE6Mn2N6O10, Mr = 788.49, De = 1.645 g/cm^3,μ(MoKa) = 0.866 mm^-1, F(000) = 235, Z = 1, the final R = 0.0425 and wR = 0.0700 for 1971 observed reflections (I 〉 2σ(I)). In the crystal structure, the manganese atom is six-coordinated by two carboxylate oxygen atoms from two different PDC ligands, one aqua ligand, and three nitrogen atoms from 2,2′-bipy and PDC ligands, giving a distorted octahedral geometry. It exhibits a three-dimensional supramolecular network defined by O-H…O hydrogen-bonding interactions. 相似文献