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861.
Kwok-Yuen Cheung King-Lung Lee Ka-Leung Lam Tsz-Ying Chan Chi-Wui Lee Chi-Wai Hui 《Journal of Analytical and Applied Pyrolysis》2011,91(1):165-182
Pyrolysis has been extensively studied in past decades as its potential to convert organic wastes into bio-fuels. Pyrolysis is an overall endothermic process but preformed exothermically at its early stage. The overall energy consumption as well as the product quality and yield are affected by the heating rate and the operation temperature. In order to reach its full potential to produce bio-fuels, the energy consumption of the process has to be minimised. An idea to reduce the pyrolysis energy consumption is observed, which suggests trapping the exothermic heat released in the beginning of the pyrolysis process and using it to fulfil the energy requirement of the endothermic reactions at the end of the process. To achieve this, the pyrolysis has to be performed in multiple stages. The operation strategy of the multi-stage pyrolysis, including the number of stages, the operating conditions (e.g. process temperature, heating rate) and residence times of each stages, have to be carefully designed to obtain the most energy saving and the best product yield. The operating strategy of a pyrolysis process therefore greatly depends on the pyrolysis kinetics and the control of heat transfers. Waste tire pyrolysis is chosen as the study example in this paper. The corresponding reaction kinetics at different heating rates are investigated via experiments. Based on the experimental results, a mathematical model integrating kinetics and heat transfers is then developed. The objective of the model is to design a suitable operation strategy for the multi-stage pyrolysis process. A four-stage strategy is finally proposed for the tire pyrolysis, which has the sequence of heating, adiabatic, heating and adiabatic. The strategy is verified by the model, and it is capable to save about 22.5% energy consumption compared to the conventional strategy. 相似文献
862.
863.
Cheung KT Trevisan J Kelly JG Ashton KM Stringfellow HF Taylor SE Singh MN Martin-Hirsch PL Martin FL 《The Analyst》2011,136(10):2047-2055
Endometriosis is the growth of endometrial tissue outside of the uterine cavity. Its aetiology remains obscure, and it is difficult to diagnose ranging from asymptomatic to debilitating disease. Mid-infrared (IR) spectroscopy has become recognised as a potential clinical diagnostic tool. Biomolecules absorb mid-IR (4000 cm(-1) to 400 cm(-1)) and from this, a biochemical-cell fingerprint in the form of an absorbance spectrum can be derived. We set out to determine if IR spectroscopy could be used to identify underlying biochemical differences between endometrial tissues growing outside of the uterus (ectopic) from endometrial tissue of the uterus (eutopic). For comparative purposes, endometrial tissues from endometriosis-free women were also obtained (benign eutopic). Attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy or transmission FTIR microspectroscopy was employed for spectral acquisition. Principal component analysis (PCA)-linear discriminant analysis (LDA) was used for chemometric analysis. A clear segregation was exhibited between the three categories independent of inter-individual confounding differences. Importantly, there was a marked difference between eutopic endometrial tissue from patients with or without endometriosis. This indicates that IR spectroscopy coupled with multivariate analysis (e.g., PCA-LDA) may provide a non-invasive diagnostic tool for endometriosis. By analysing the underlying biochemistry of these endometrial tissues, this approach may facilitate a better understanding of this pathology. 相似文献
864.
The latest CDF anomaly, the excess of dijet events in the invariant-mass window 120-160 GeV in associated production with a W boson, can be explained by a baryonic Z' model in which the Z' boson has negligible couplings to leptons. Although this Z' model is hardly subject to the Drell-Yan constraint from Tevatron, it is constrained by the dijet data from UA2 (√s=630 GeV), and the precision measurements at LEP through the mixing with the SM Z boson. We show that under these constraints this model can still explain the excess in the M(jj)~120-160 GeV window, as well as the claimed cross section σ(WZ')~4 pb. Implications at the Tevatron would be the associated production of γZ', ZZ', and Z'Z' with the Z'→jj. We show that with tightened jet cuts and improved systematic uncertainties both γZ'→γjj and ZZ'→?(+)?(-) jj channels could be useful to probe this model at the Tevatron. 相似文献
865.
Hongjuan Dong Sau Ha Cheung Yimin Liang Baojiang Wang Rajkumar Ramalingam Ping Wang Hongyan Sun Shuk Han Cheng Yun Wah Lam 《Electrophoresis》2013,34(13):1957-1964
Organelle‐specific cell‐permeable fluorescent dyes are invaluable tools in cell biology as they reveal intracellular dynamics in living cells. Mitrotracker is a family of dyes that strongly label the mitochondrion, a key organelle associated with many crucial cellular functions. Despite the popularity of these dyes, little is known about the molecular mechanism behind their staining specificity. Here, we aimed to identify the protein targets of one member of this dye family, mitotracker red (MTR), by 2DE and MS. MTR bound to cellular proteins covalently, and its fluorescence persisted even after cell lysis, protein solubilization, denaturation, and electrophoresis. This enabled us to display MTR‐labeled proteins by 2DE. The MTR‐specific fluorescent signals on the gel revealed the spots that contained MTR‐conjugated proteins. These spots were analyzed by MS, resulting into the identification of ten proteins. We discovered that one major target is the mitochondrial protein HSP60 and that MTR staining could induce production of HSP60, predisposing cells to heat shock‐like responses. The identification of the molecular targets of biological dyes, or “stainomics,” can help correlate their intracellular staining properties with biochemical affinities. We believe this approach can be applied to a wide range of fluorescent probes. 相似文献
866.
Dr. Amanda G. Jarvis Dr. Petr E. Sehnal Dr. Somia E. Bajwa Dr. Adrian C. Whitwood Dr. Xiangbiao Zhang Man Sing Cheung Prof. Dr. Zhenyang Lin Prof. Dr. Ian J. S. Fairlamb 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(19):6034-6043
A multidentate and flexible diolefin–diphosphine ligand, based on the dibenzylidene acetone core, namely dbaphos ( 1 ), is reported herein. The ligand adopts an array of different geometries at Pt, Pd and Rh. At PtII the dbaphos ligand forms cis‐ and trans‐diphosphine complexes and can be defined as a wide‐angle spanning ligand. 1H NMR spectroscopic analysis shows that the β‐hydrogen of one olefin moiety interacts with the PtII centre (an anagostic interaction), which is supported by DFT calculations. At Pd0 and RhI, the dbaphos ligand exhibits both olefin and phosphine interactions with the metal centres. The Pd0 complex of dbaphos is dinuclear, with bridging diphosphines. The complex exhibits the coordination of one olefin moiety, which is in dynamic exchange (intramolecular) with the other “free” olefin. The Pd0 complex of dbaphos reacts with iodobenzene to afford trans‐[PdII(dbaphos)I(Ph)]. In the case of RhI, dbaphos coordinates to form a structure in which the phosphine and olefin moieties occupy both axial and equatorial sites, which stands in contrast to a related bidentate olefin, phosphine ligand (“Lei” ligand), in which the olefins occupy the equatorial sites and phosphines the axial sites, exclusively. 相似文献
867.
Multistage dynamic networks with random arc capacities (MDNRAC) have been successfully used for modeling various resource allocation problems in the transportation area. However, solving these problems is generally computationally intensive, and there is still a need to develop more efficient solution approaches. In this paper, we propose a new heuristic approach that solves the MDNRAC problem by decomposing the network at each stage into a series of subproblems with tree structures. Each subproblem can be solved efficiently. The main advantage is that this approach provides an efficient computational device to handle the large-scale problem instances with fairly good solution quality. We show that the objective value obtained from this decomposition approach is an upper bound for that of the MDNRAC problem. Numerical results demonstrate that our proposed approach works very well. 相似文献
868.
The widespread use of wormlike micellar solutions is commonly found in household items such as cosmetic products, industrial fluids used in enhanced oil recovery and as drag reducing agents, and in biological applications such as drug delivery and biosensors. Despite their extensive use, there are still many details about the microscopic micellar structure and the mechanisms by which wormlike micelles form under flow that are not clearly understood. Microfluidic devices provide a versatile platform to study wormlike micellar solutions under various flow conditions and confined geometries. A review of recent investigations using microfluidics to study the flow of wormlike micelles is presented here with an emphasis on three different flow types: shear, elongation, and complex flow fields. In particular, we focus on the use of shear flows to study shear banding, elastic instabilities of wormlike micellar solutions in extensional flow (including stagnation and contraction flow field), and the use of contraction geometries to measure the elongational viscosity of wormlike micellar solutions. Finally, we showcase the use of complex flow fields in microfluidics to generate a stable and nanoporous flow-induced structured phase (FISP) from wormlike micellar solutions. This review shows that the influence of spatial confinement and moderate hydrodynamic forces present in the microfluidic device can give rise to a host of possibilities of microstructural rearrangements and interesting flow phenomena. 相似文献
869.
The intracellular level of glutathione (GSH) was significantly decreased after the addition of andrographolide (1) to cell cultures of HepG2. When the molecular interaction between andrographolide and GSH was investigated under a condition mimicking the in vivo environment, we observed that the level of GSH dropped in the presence of andrographolide. Stoichiometric analysis indicates that the reaction between these two reactants was 1 to 1 at pH 7 and followed second order kinetics. The activation energy of the overall reaction was 41.9+/-10 kJ x mol(-1) according to the Arrhenius equation. Using a micro-liquid-liquid extraction method followed by micellar electrokinetic chromatographic separation, two major products were isolated and identified, and their chemical structures were determined as 14-deoxy-12-(glutathione-amino)-andrographolide (2) and 14-deoxy-12-(glutathione-S-yl)-andrographolide (3). Based on these structural findings, a hypothetical mechanism of reaction between glutathione and andrographolide was proposed. It is concluded that the alpha,beta-unsaturated lactone moiety of andrographolide reacts with GSH through a Michael addition followed by dehydration of the adduct. 相似文献
870.
Carina Hey Pui Cheung Dr. Tin Hang Chong Dr. Tongyao Wei Dr. Han Liu Prof. Dr. Xuechen Li 《Angewandte Chemie (International ed. in English)》2023,62(10):e202217150
Recently, ortho-phthalaldehyde (OPA) is experiencing a renascence for the modification of proteins and peptides through OPA-amine two-component reactions for bioconjugation and intramolecular OPA-amine-thiol three-component reactions for cyclization. Historically, small thiol molecules were used in large excess to allow for the intermolecular OPA-amine-thiol reaction forming 1-thio-isoindole derivatives. In this study, we discovered that guanidine could serve as an effective additive to switch the intermolecular OPA-amine-thiol three-component reaction to a stoichiometric process and enable the modular construction of peptide-peptide, and peptide-drug conjugate structures. Thus, 12 model peptide-peptide conjugates have been synthesized from unprotected peptides featuring all proteinogenic residues. Besides, 6 peptide-drug conjugates have been prepared in one step, with excellent conversions and isolated yields. In addition, a conjugate product has been further functionalized by utilizing a premodified OPA derivative, demonstrating the versatility and flexibility of this reaction. 相似文献