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61.
荧光光谱法研究木犀草素、芹菜素或葛根素与牛血清白蛋白的相互作用机理 总被引:1,自引:0,他引:1
利用紫外可见光谱和荧光光谱法研究三种黄酮类药物木犀草素、芹菜素和葛根素与牛血清白蛋白(BSA)在不同温度下(292 K和311 K)的相互作用。结果表明:三种黄酮类药物与牛血清白蛋白形成复合物导致牛血清白蛋白荧光猝灭,试验数据采用Stern-Volmer拟合方程处理及双对数方程处理,进一步证明结合反应引起的荧光猝灭属于静态猝灭。采用位点结合模型公式、热力学公式和F rster非辐射能量转移理论计算了结合常数、结合位点数及作用力类型以及结合距离。 相似文献
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Tuuli A. Hakala Sarah Davies Dr. Zenon Toprakcioglu Dr. Barbara Bernardim Dr. Gonçalo J. L. Bernardes Prof. Tuomas P. J. Knowles 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(27):5965-5969
Nanoparticles are widely studied as carrier vehicles in biological systems because their size readily allows access through cellular membranes. Moreover, they have the potential to carry cargo molecules and as such, these factors make them especially attractive for intravenous drug delivery purposes. Interest in protein-based nanoparticles has recently gained attraction due to particle biocompatibility and lack of toxicity. However, the production of homogeneous protein nanoparticles with high encapsulation efficiencies, without the need for additional cross-linking or further engineering of the molecule, remains challenging. Herein, we present a microfluidic 3D co-flow device to generate human serum albumin/celastrol nanoparticles by co-flowing an aqueous protein solution with celastrol in ethanol. This microscale co-flow method resulted in the formation of nanoparticles with a homogeneous size distribution and an average size, which could be tuned from ≈100 nm to 1 μm by modulating the flow rates used. We show that the high stability of the particles stems from the covalent cross-linking of the naturally present cysteine residues within the particles formed during the assembly step. By choosing optimal flow rates during synthesis an encapsulation efficiency of 75±24 % was achieved. Finally, we show that this approach achieves significantly enhanced solubility of celastrol in the aqueous phase and, crucially, reduced cellular toxicity. 相似文献
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用分子对接方法及紫外-可见吸收光谱、同步荧光光谱、三维荧光光谱等实验手段研究了噻螨酮(HEX)与人血清白蛋白(HSA)的相互作用及对HSA构象的影响.预测结果表明,HEX能与HSA发生相互作用,且作用位点site II比site I的打分小约4.5.实验结果表明,HEX猝灭HSA的内源荧光且作用机制为静态猝灭;HEX使HSA周围的微环境发生变化,导致蛋白质的肽链结构改变;298和291 K时HEX与HSA相互作用的结合常数(KA)和结合位点数分别为7.35×103 mol/L、0.82和1.02×104 mol/L、0.86,证实HEX仅在site II存在作用位点;HEX与Trp214的结合距离为3.01 nm,作用力主要为氢键、范德华力和疏水作用力.这些研究所获得的多种信息有助于在分子水平上理解农药对人体造成的毒性及可能的生物累积性. 相似文献
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Shah Hussain Cornelia Pezzei Yüksel Güzel Matthias Rainer Christian W. Huck Günther K. Bonn 《Analytica chimica acta》2014
An efficient blood plasma clean-up method was developed, where methanol protein precipitation was applied, followed by zirconium silicate assisted exclusion of residual proteins. A strong binding of zirconium (IV) silicate to the proteins enabled the elimination of remaining proteins after solvent deproteinization through a rapid solid-phase extraction (SPE) procedure. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF MS) was used for monitoring the proteins during clean-up practice applied to human plasma samples. The proteins were quantified by colorimetric detection using the bicinchoninic acid (BCA) assay. The presented analytical strategy resulted in the depletion of >99.6% proteins from human plasma samples. Furthermore, high-performance liquid chromatography hyphenated to diode-array and electrospray ionization mass spectrometric detection (HPLC–DAD/ESI MS) was applied for qualitative and quantitative analysis of the caffeoylquinic acids (CQAs) and their metabolites in human plasma. The procedure demonstrated high recoveries for the standard compounds spiked at different concentrations. Cynarin and chlorogenic acid were recovered in the range of 81–86% and 78–83%, respectively. Caffeic acid was extracted in the excess of 89–92%, while ferulic acid and dihydroxyhydrocinnamic acid showed a recovery of 87–91% and 92–95%, respectively. The method was partially validated in accordance with FDA-Industry Guidelines for Bioanalytical Method Validation (2001). The presented scheme improves the clean-up efficacy of the methanol deproteinization, significantly reduces the matrix effects and provides a great analytical tool for the isolation of small molecules from human plasma. 相似文献
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Small peptides in serum are potential biomarkers for the diagnosis of cancer and other diseases. The identification of peptide biomarkers in human plasma/serum has become an area of high interest in medical research. However, the direct analysis of peptides in serum samples using mass spectrometry is challenging due to the low concentration of peptides and the high abundance of high-molecular-weight proteins in serum, the latter of which causes severe signal suppression. Herein, we reported that porous semiconductor-noble metal hybrid nanostructures can both eliminate the interference from large proteins in serum samples and significantly enhance the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) yields of peptides captured on the nanostructure. Serum peptide fingerprints with high fidelity can be acquired rapidly, and successful discrimination of colorectal cancer patients based on peptide fingerprints is demonstrated. 相似文献
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The interaction of La3+ to bovine serum albumin (BSA) has been investigated mainly by fluorescence spectra, UV-vis absorption spectra, and circular dichroism (CD) under simulative physiological conditions. Fluorescence data revealed that the quenching mechanism of BSA by La3+ was a static quenching process and the binding constant is 1.75×104 L mol−1 and the number of binding sites is 1 at 289 K. The thermodynamic parameters (ΔH=−20.055 kJ mol−1, ΔG=−23.474 kJ mol−1, and ΔS=11.831 J mol−1 K−1) indicate that electrostatic effect between the protein and the La3+ is the main binding force. In addition, UV-vis, CD, and synchronous fluorescence results showed that the addition of La3+ changed the conformation of BSA. 相似文献
70.
Spectrofluorimetric study on the interaction between antimicrobial drug sulfamethazine and bovine serum albumin 总被引:1,自引:0,他引:1
Abdulilah Dawoud Bani-Yaseen 《Journal of luminescence》2011,131(5):1042-1047
The interaction between the antimicrobial drug sulfamethazine (STM) and bovine serum albumin (BSA) has been studied using steady state and synchronous fluorescence spectroscopy. Fluorescence emission data revealed that BSA (2×10−6 M) fluorescence was statically quenched by STM at various concentrations, which implies that STM-BSA complex has been formed. The fluorescence emission data was analyzed via applying the Stern-Volmer analysis in combination with thermodynamic investigation, where obtained results revealed that quenching is static with quenching constants of 2.371, 1.658, and 0.916×105 M−1 at 298, 304, and 310 K, respectively. Binding constants and number of binding sites at different temperatures were also determined by applying the Scatchard method, which in turn were used to construct the van't Hoff plot in order to estimate the enthalpy (ΔH) and entropy changes (ΔS) for the complexation process. An average of 1.00±0.17 was estimated for the number of sites of BSA, which indicated that STM binds to BSA with stoichiometric ratio of 1:1. The values that were estimated from the van't Hoff plot for ΔH and (ΔS) were −36.8 kJ mol−1 and −14.9 J mol−1 K−1, respectively, which indicate that the STM-BSA complex is stabilized with hydrogen bonds and van der Waals interactions. Synchronous fluorescence data was obtained at Δλ of 15 and 60 nm, where obtained results confirmed that STM binds to BSA at the tryptophan residue (Trp. 213). In addition, the distance between STM and the Trp. 213 was estimated via employing the Förster's non-radiative energy-transfer theory, and was found to be 2.73 nm, which in turn indicated that STM can bind to BSA with high probability. 相似文献