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Michele Menotta Sara Biagiotti Laura Streppa Luigia Rossi Mauro Magnani 《Analytica chimica acta》2015
In the present paper we describe an atomic force microscopy (AFM)-based method for the quantitative analysis of FK506 (Tacrolimus) in whole blood (WB) samples. Current reference methods used to quantify this immunosuppressive drug are based on mass spectrometry. In addition, an immunoenzymatic assay (ELISA) has been developed and is widely used in clinic, even though it shows a small but consistent overestimation of the actual drug concentration when compared with the mass spectrometry method. The AFM biosensor presented herein utilises the endogen drug receptor, FKBP12, to quantify Tacrolimus levels. The biosensor was first assayed to detect the free drug in solution, and subsequently used for the detection of Tacrolimus in blood samples. The sensor was suitable to generate a dose–response curve in the full range of clinical drug monitoring. A comparison with the clinically tested ELISA assay is also reported. 相似文献
204.
A Pd‐isatin Schiff base complex immobilized onγ‐Fe2O3 (Pd‐isatin Schiff base‐γ‐Fe2O3) was synthe‐sized and characterized by Fourier transform infrared, scanning electron microscopy, high resolu‐tion tr... 相似文献
205.
Ruthenium‐Catalyzed Oxidative Coupling of Primary Amines with Internal Alkynes through CH Bond Activation: Scope and Mechanistic Studies
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Sara Ruiz Dr. Pedro Villuendas Dr. Manuel A. Ortuño Prof. Dr. Agustí Lledós Dr. Esteban P. Urriolabeitia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(23):8626-8636
The oxidative coupling of primary amines with internal alkynes catalyzed by Ru complexes is presented as a general atom‐economy methodology with a broad scope of applications in the synthesis of N‐heterocycles. Reactions proceed through regioselective C?H bond activation in 15 minutes under microwave irradiation or in 24 hours with conventional heating. The synthesis of 2,3,5‐substituted pyridines, benzo[h]isoquinolines, benzo[g]isoquinolines, 8,9‐dihydro‐benzo[de]quinoline, 5,6,7,8‐tetrahydroisoquinolines, pyrido[3,4g]isoquinolines, and pyrido[4,3g]isoquinolines is achievable depending on the starting primary amine used. DFT calculations on a benzylamine substrate support a reaction mechanism that consists of acetate‐assisted C?H bond activation, migratory‐insertion, and C?N bond formation steps that involve 28–30 kcal mol?1. The computational study is extended to additional substrates, namely, 1‐naphthylmethyl‐, 2‐methylallyl‐, and 2‐thiophenemethylamines. 相似文献
206.
A representation of an object in a category is an abelian group in the corresponding comma category. In this paper, we derive the formulas describing linear representations of objects in the category of formal loops and formal loop homomorphisms and apply them to obtain a new approach to the representation theory of formal Moufang loops and Malcev algebras based on Moufang elements. Certain ‘non-associative Moufang symmetry’ of groups is revealed. 相似文献
207.
Kadir Sentosun Marta N. Sanz Ortiz K. Joost Batenburg Luis M. Liz‐Marzán Sara Bals 《Particle & Particle Systems Characterization》2015,32(12):1063-1067
Characterization of core–shell type nanoparticles in 3D by transmission electron microscopy (TEM) can be very challenging. Especially when both heavy and light elements coexist within the same nanostructure, artifacts in the 3D reconstruction are often present. A representative example would be a particle comprising an anisotropic metallic (Au) nanoparticle coated with a (mesoporous) silica shell. To obtain a reliable 3D characterization of such an object, a dose‐efficient strategy is proposed to simultaneously acquire high‐angle annular dark‐field scanning TEM and annular dark‐field tilt series for tomography. The 3D reconstruction is further improved by applying an advanced masking and interpolation approach to the acquired data. This new methodology enables us to obtain high‐quality reconstructions from which also quantitative information can be extracted. This approach is broadly applicable to investigate hybrid core–shell materials. 相似文献
208.
Studies involving metal enhancement effects have gained popularity, and enhancement of fluorescence due to the close proximity of a dye molecule to a metal nanoparticle is well documented. Although enhancement of singlet oxygen production by metal has been reported, studies are relatively scarce and so far only stationary silver island films have been proven to be adequate to do so. Herein, we describe the synthesis and characterization of core–shell nanoparticles on which a photosensitizer acting as source of singlet oxygen has been covalently attached to the nanoparticle surface. As a proof of concept, silver nanoparticles with a diameter around 68 nm were chosen as the metallic core, and were coated by a silica shell of about 22 nm in thickness. The silica shell plays a dual role as a spacer and a medium onto which the photosensitizer, rose bengal (RB), has been covalently attached. These novel core–shell nanoparticles allow for the amplification of singlet oxygen production by 3.8 times, which is similar to the amplification found for RB in proximity of silver island films. 相似文献
209.
Tayebeh Hosseinnejad Saeed Dehghanpour Sara Basiri-nasab 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(11):2004-2011
The main goal of this research is to investigate the structural and thermochemical aspects of complexation between La3+ with tetrapropyl malonamide (TPMA) and tetrapropyl diglycolamide (TPDGA) ligands via density functional theory (DFT) methods. In this respect, the structural parameters of [La-TPMA]3+ and [La-TPDGA]3+ complexes have been calculated and compared with the available X-ray crystallographic data. These comparisons revealed that both calculated structural values using B3LYP and M06 are in a reliable agreement with X-ray crystal structure with a near accuracy. In the next step, the more efficiency of diglycolamides in comparison with malonamides in the extraction of La3+ have been analyzed by calculating thermochemical properties of the complexation. It should be stated that this issue has been observed in many experimental elucidations. In the next step, the inclusion of solvent effects on thermodynamical properties of complexation has been evaluated via polarized continuum model (PCM) calculations. In this context, enthalpy and Gibbs free energy changes have been determined in the presence of three solvents, chloroform, toluene and n-hexane. Our obtained results demonstrate that using n-hexane as solvent is more favorable thermodynamically than chloroform and toluene that confirms the previously observed experiments. Finally, the bond orders of some selected key bonds in TPMA and TPDGA ligands and their corresponded La3+ complexes have been evaluated comparatively to analyze the electronic features of coordination in [La-TPMA]3+ and [La-TPDGA]3+ complexes. 相似文献
210.
Cold represents one of the major abiotic factors influencing plant growth and development worldwide. We analysed the long-term responsiveness of an Iranian spring wheat (cv. Kohdasht) to cold from a proteomic point of view, in order to unravel the molecular mechanisms helping a cold-sensitive cultivar to survive exposure to suboptimal temperatures. Plants were grown at 20 or 4°C until entering the reproductive stage and a cross-comparison on the leaf proteomes was performed. Quantitative analyses on protein alterations occurring upon low-temperature exposure showed a reinforcement in ascorbate recycling (dehydroascorbate reductase, ascorbate peroxidase) and protein processing (proteasome subunit, cysteine proteinase), as well as the accumulation of the enzyme devoted to tetrapyrrole resynthesis (glutamate semialdehyde aminomutase). In contrast, among proteins down-regulated after cold stress, we could identify some key Krebs cycle enzymes (isocitrate dehydrogenase, malate dehydrogenase), together with many photosynthesis-related proteins (oxygen-evolving complex proteins, ATP synthase subunits, ferredoxin NADPH oxidoreductase and some Calvin cycle enzymes). Physiological and biochemical parameters (such as shoot apex dissection, chlorophyll, proline and sugar content determination) sustained proteomics findings allowing the present research to contribute to the current knowledge on these long-term responses, which may be crucial to stress adaptation under field conditions. 相似文献