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221.
We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_{1} of the neutron and 3He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c);{2}. Global duality is observed for the spin-structure function g_{1} down to at least Q;{2}=1.8 (GeV/c);{2} in both targets. We have also formed the photon-nucleon asymmetry A1 in the resonance region for 3He and found no strong Q2 dependence above 2.2 (GeV/c);{2}.  相似文献   
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Presence of cyclobutane rings in bioactive natural products makes them a popular synthetic target. Most common strategy for synthesizing cyclobutanes is [2+2] cycloaddition, which is usually facilitated by using ultraviolet radiation and catalysts. Herein we report the design and synthesis of densely functionalized cyclobutanes by alleviating these drawbacks and using sunlight. Further, we identified the putative mechanism of the transformation based on kinetic, fluorescence and crystallographic studies and evaluated biological activities of the products against MCF7 cell lines. The rational design of the olefinic substrates was based on their UV–vis spectra. The generic aspect of the reaction was elucidated by the syntheses of diverse analogs of cyclobutanes. Further, crystal structures and UV–vis spectra of the olefinic partners assisted us in rationalizing the stereoselectivity of the heterodimers. We believe this energy-efficient mild approach will provide a substantial contribution to the existing repertoire of strategies to regio- and stereoselectively access cyclobutanes.  相似文献   
225.
The reduction of TipMCl3 (Tip=2,4,6‐triisopropylphenyl) (M=Si, Ge) with KC8 in the presence of cyclic alkyl(amino) carbene (cAAC) afforded the acyclic silanylidene and germanylidene anions in the form of potassium salt [K(cAAC)MTip]2 (M=Si ( 1 ); Ge ( 2 )). The silanylidene and germanylidene anions are valence‐isoelectronic to the well‐studied phosphinidene and are a new class of acyclic anions of Group 14. Compounds 1 and 2 were isolated and well characterized by NMR and single‐crystal X‐ray structure analysis. Furthermore, the structure and bonding of compounds 1 and 2 was investigated by computational methods.  相似文献   
226.
Dualizing Complex and the Canonical Element Conjecture II   总被引:1,自引:0,他引:1  
In this paper we continue our study of the Canonical ElementConjecture (henceforth C.E.C.) via the dualizing complex. Throughoutthe work (A, m, k) will denote a noetherian complete local ringA of dimension n, m its maximal ideal and k=A/m. Since A iscomplete, we can find a complete local Gorenstein ring (R, mR,k) (complete intersection) such that dim R=dim A and A=R/I.Let denote the canonical module of A, that is, =HomR (A, R),which may be identified with the annihilator of I in R, an idealof R. When A is a domain, we change notation and denote I byP; in this case P is a height 0 prime ideal of R.  相似文献   
227.
Transparent conducting oxides, such as doped indium oxide, zinc oxide, and cadmium oxide (CdO), have recently attracted attention as tailorable materials for applications in nanophotonic and plasmonic devices such as low‐loss modulators and all‐optical switches due to their tunable optical properties, fast optical response, and low losses. In this work, optically induced extraordinarily large reflection changes (up to 135%) are demonstrated in bulk CdO films in the mid‐infrared wavelength range close to the epsilon near zero (ENZ) point. To develop a better understanding of how doping level affects the static and dynamic optical properties of CdO, the evolution of the optical properties with yttrium (Y) doping is investigated. An increase in the metallicity and a blueshift of the ENZ point with increasing Y‐concentrations is observed. Broadband all‐optical switching from near‐infrared to mid‐infrared wavelengths is demonstrated. The major photoexcited carrier relaxation mechanisms in CdO are identified and it is shown that the relaxation times can be significantly reduced by increasing the dopant concentration in the film. This work could pave the way to practical dynamic and passive optical and plasmonic devices with doped CdO spanning wavelengths from the ultraviolet to the mid‐infrared region.  相似文献   
228.
Since its first emergence in 2004, the high-entropy alloy (HEA) concept has aimed at stabilizing single- or dual-phase multi-element solid solutions through high mixing entropy. Here, this strategy is changed and renders such massive solid solutions metastable, to trigger spinodal decomposition for improving the alloys’ magnetic properties. The motivation for starting from a HEA for this approach is to provide the chemical degrees of freedom required to tailor spinodal behavior using multiple components. The key idea is to form Fe-Co enriched regions which have an expanded volume (relative to unconstrained Fe-Co), due to coherency constraints imposed by the surrounding HEA matrix. As demonstrated by theory and experiments, this leads to improved magnetic properties of the decomposed alloy relative to the original solid solution matrix. In a prototype magnetic FeCoNiMnCu HEA, it is shown that the modulated structures, achieved by spinodal decomposition, lead to an increase of the Curie temperature by 48% and a simultaneous increase of magnetization by 70% at ambient temperature as compared to the homogenized single-phase reference alloy. The findings thus open a pathway for the development of advanced functional HEAs.  相似文献   
229.
Interconnection between our existing optical packet and circuit integrated network (OPCInet) and an ecosystem for network service provisioning named ChoiceNet enables network service providers to provide diverse services and realize control driven by the providers. In this paper, we design and implement control interfaces for the interconnection, which enables each ChoiceNet provider to explicitly control both OPCInet- and OpenFlow-based networks by use of a single common interface with proprietary/easily modifiable message formats for all control functions. We construct an experimental setup between the USA and Japan, and demonstrate that the OPCInet and an OpenFlow-based network placed in Japan are successfully controlled by request from the ChoiceNet provider installed in the USA. We also show that the time required to complete Telnet access to the OPCInet C-plane for each control is no more than 150 ms over the long distance from the USA to Japan.  相似文献   
230.
The synthesis and the characterization of a series of DTPA-bis(amide) conjugates of tranexamic acid (L1), its esters (L2-L6), and their Gd(III) complexes of the type [Gd(L)(H2O)].nH2O (L = L1-L6) are described. Except for the case of , all Gd-complexes exhibit greatly enhanced R1 relaxivity. Highest R1 reaches up to 12.9 mM(-1) s(-1) for [Gd(L2)(H2O)]. Such high relaxivity is reflected in the intensity enhancement of the in vivo MRI study on H-ras transgenic mice bearing hepatic tumor when employing [Gd(L2)(H2O)] as an MRI contrast agent. Thermodynamic stability constants, conditional stability constants, and the pM values demonstrate higher stability of [Gd(L)(H2O)].nH2O (L =L1-L6) than Omniscan under physiological conditions. The MTT assay performed on these complexes reveals cytotoxicity as low as that for Omniscan in the concentration range required to obtain intensity enhancement in the in vivo MRI study.  相似文献   
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