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1.
Traditional cell/particle isolation methods are time-consuming and expensive and can lead to morphology disruptions due to high induced shear stress. To address these problems, novel lab-on-a-chip-based purification methods have been employed. Among various methods introduced for the separation and purification of cells and synthetics particles, acoustofluidics has been one of the most effective methods. Unlike traditional separation techniques carried out in clinical laboratories based on chemical properties, the acoustofluidic process relies on the physical properties of the sample. Using acoustofluidics, manipulating cells and particles can be achieved in a label-free, contact-free, and highly biocompatible manner. To optimize the functionality of the platform, the numerical study should be taken into account before conducting experimental tests to save time and reduce fabrication expenses. Most current numerical studies have only considered one-dimensional harmonic standing waves to simulate the acoustic pressure distribution. However, one-dimensional simulations cannot calculate the actual acoustic pressure distribution inside the microchannel due to its limitation in considering longitudinal waves. To address this limitation, a two-dimensional numerical simulation was conducted in this study. Our numerical simulation investigates the effects of the platform geometrical and operational conditions on the separation efficiency. Next, the optimal values are tested in an experimental setting to validate these optimal parameters and conditions. This work provides a guideline for future acoustofluidic chip designs with a high degree of reproducibility and efficiency.  相似文献   
2.
Surface plasmon can trigger or accelerate many photochemical reactions, especially useful in energy and environmental industries. Recently, molecular adsorption has proven effective in modulating plasmon-mediated photochemistry, however the realized chemical reactions are limited and the underlying mechanism is still unclear. Herein, by using in situ dark-field optical microscopy, the plasmon-mediated oxidative etching of silver nanoparticles (Ag NPs), a typical hot-hole-driven reaction, is monitored continuously and quantitatively. The presence of thiol or thiophenol molecules is found essential in the silver oxidation. In addition, the rate of silver oxidation is modulated by the choice of different thiol or thiophenol molecules. Compared with the molecules having electron donating groups, the ones having electron accepting groups accelerate the silver oxidation dramatically. The thiol/thiophenol modulation is attributed to the modulation of the charge separation between the Ag NPs and the adsorbed thiol or thiophenol molecules. This work demonstrates the great potential of molecular adsorption in modulating the plasmon-mediated photochemistry, which will pave a new way for developing highly efficient plasmonic photocatalysts.  相似文献   
3.
Cinnarizine is a weak base, which can produce supersaturation and precipitation during gastrointestinal transit, affecting its absorption in vivo. Therefore, it is necessary to investigate whether the oral bioavailability of cinnarizine can be improved after co-administration with precipitation inhibitors or not. In order to evaluate the pharmacokinetic behavior of cinnarizine in rats, a simple, rapid, sensitive, and environmentally friendly supercritical fluid chromatography-tandem mass spectrometric method was established and validated. In this method, flunarizine, a structural analogue of cinnarizine, was selected as the internal standard, and cinnarizine was extracted from rat plasma using evaporation-free liquid–liquid extraction method. The analytes were separated on a Torus 1-AA column (3.0 mm × 100 mm, 1.7 μm) within 2.0 min, using a gradient elution procedure. The transitions of cinnarizine and flunarizine were m/z 369.1 → 167.1 and m/z 405.1 → 203.1, respectively. Cinnarizine showed good linear correlation in the range of 1–500 ng/ml with a lower limit of quantification of 1 ng/ml. The intra- and interday precision and accuracy of all quality control samples were within ±15%. This high-throughput, accurate, sensitive, and reproducible method has been successfully applied to study the effects of the precipitation inhibitor cinnarizine on the pharmacokinetics in rats.  相似文献   
4.
The chiral separation of various analytes (dichlorprop, mecoprop, ibuprofen, and ketoprofen) was demonstrated with different cyclodextrins as mobile phase additives in open-tubular liquid chromatography using a stationary pseudophase semipermanent coating. The stable coating was prepared by a successive multiple ionic layer approach using poly(diallyldimethylammonium chloride), polystyrene sulfonate, and didodecyldimethyl ammonium bromide. Increasing concentrations (0–0.2 mM) of various native and derivatized cyclodextrins in 25 mM sodium tetraborate (pH 9.2) were investigated. Chiral separation was achieved for the four test analytes using 0.05–0.1 mM β-cyclodextrin (resolution between 1.11 and 1.34), γ-cyclodextrin (resolution between 0.78 and 1.27), carboxymethyl-β-cyclodextrin (resolution between 1.64 and 2.59), and 2-hydroxypropyl-β-cyclodextrin (resolution between 0.71 and 1.76) with the highest resolutions obtained with 0.1 mM carboxymethyl-β-cyclodextrin. %RSD values were <10%. This is the first demonstration of chiral open-tubular liquid chromatography using achiral chromatographic coatings and cyclodextrins as mobile phase additives.  相似文献   
5.
Adsorptive separation of C2H6 from C2H4 by adsorbents is an energy-efficient and promising method to boost the polymer grades C2H4 production. However, that C2H6 and C2H4 display very similar physical properties, making their separation extremely challenging. In this work, by regulating the pore environment in a family of chitosan-based carbon materials (C-CTS-1, C-CTS-2, C-CTS-4, and C-CTS-6)- we target ultrahigh C2H6 uptake and C2H6/C2H4 separation, which exceeds most benchmark carbon materials. Explicitly, the C2H6 uptake of C-CTS-2 (166 cm3/g at 100 kPa and 298 K) has the second-highest adsorption capacity among all the porous materials. In addition, C-CTS-2 gives C2H6/C2H4 selectivity of 1.75 toward a 1:15 mixture of C2H6/C2H4. Notably, the adsorption enthalpies for C2H6 in C-CTS-2 are low (21.3 kJ/mol), which will facilitate regeneration in mild conditions. Furthermore, C2H6/C2H4 separation performance was confirmed by binary breakthrough experiments. Under different ethane/ethylene ratios, C-CTS-X extracts a low ethane concentration from an ethane/ethylene mixture and produces high-purity C2H4 in one step. Spectroscopic measurement and diffraction analysis provide critical insight into the adsorption/separation mechanism. The nitrogen functional groups on the surface play a vital role in improving C2H6/C2H4 selectivity, and the adsorption capacities depend on the pore size and micropore volume. Moreover, these robust porous materials exhibit outstanding stability (up to 800 °C) and can be easily prepared on a large scale (kg) at a low cost (~$26 per kg), which is very significant for potential industrial applications.  相似文献   
6.
多孔液体(Porous Liquids, PLs)是一类结合了多孔固体永久性孔隙与液态流动性优势的新材料. 自2007年, PLs的概念被首次提出以来, 其在合成策略与应用领域方面均取得了较大的突破. 然而, 传统的PLs因高黏度、高密度、高熔点与高原材料成本等缺陷极大程度制约了其在流动工业系统中的大规模应用. 因此, 迫切需要寻求理想的位阻溶剂用于制备先进的多孔液体. 离子液体(Ionic Liquids, ILs)因独特的可调节物理特性、非挥发性、高稳定性、易获得、经济性高、低再生能耗等特性, 使其成为构筑PLs中最具有应用前景的理想溶剂之一. 在过去的5年间, 基于多种ILs与先进多孔固体(如有机笼、金属有机框架、中空碳、沸石、多孔聚合物等)制备的多孔离子液体(Porous Ionic Liquids, PILs)被陆续报道. PILs独特的永久性孔隙、无溶剂挥发、再生能力强、黏度可调、低熔点、高稳定性等特性加快了其在气体吸附、分离、催化、萃取、分子分离等领域的快速发展. 本综述围绕PILs的构筑策略、特性、应用领域等阐述了其研究进展. 最后, 对PILs在制备中存在的挑战与未来的研究方向进行了归纳与展望.  相似文献   
7.
调节待测体系的pH值是配位滴定中一种重要的选择性滴定手段。采用CTE1.0程序计算了不同酸度条件下的终点误差,同时用配位滴定法测定了模拟样品和市售药品中的锌含量。计算结果和实测结果均表明,在不含钙离子的待测体系中,测定锌离子含量的合适酸度条件为pH=6;在钙、锌混合离子溶液中,测定锌含量的合适酸度条件为pH=5。平行测定实验的相对标准误差为1.63%,加标回收率为99.1%-101.8%。  相似文献   
8.
Continuous microporous membranes are widely studied for gas separation, due to their low energy premium and strong molecular specificity. Porous aromatic frameworks (PAFs) with their exceptional stability and structural flexibility are suited to a wide range of separations. Main-stream PAF-based membranes are usually prepared with polymeric matrices, but their discrete entities and boundary defects weaken their selectivity and permeability. The synthesis of continuous PAF membranes is still a major challenge because PAFs are insoluble. Herein, we successfully synthesized a continuous PAF membrane for gas separation. Both pore size and chemistry of the PAF membrane were modified by ion-exchange, resulting in good selectivity and permeance for the gas mixtures H2/N2 and CO2/N2. The membrane with Br? as a counter ion in the framework exhibited a H2/N2 selectivity of 72.7 with a H2 permeance of 51844 gas permeation units (GPU). When the counter ions were replaced by BF4?, the membrane showed a CO2 permeance of 23058 GPU, and an optimized CO2/N2 selectivity of 60.0. Our results show that continuous PAF membranes with modifiable pores are promising for various gas separation situations.  相似文献   
9.
太阳能驱动的光电化学(PEC)水分解可以有效地将太阳能转化为化学能,作为解决环境排放和能源危机最具前景的途径之一,已经引起了科学界的广泛关注.PEC水分解系统由两个半反应组成:在光阳极上的析氧反应(OER)和光阴极上的析氢反应(HER).PEC系统的太阳能转化效率主要由光阳极/电解质界面的OER过程所决定,这是一个非常复杂且涉及质子偶联的多步四电子转移过程.钒酸铋(BiVO4)是应用于PEC水分解的典型且具有实际应用前景的光阳极材料之一.然而,由于不良的表面电荷转移、电荷在光阳极/电解质结面处的表面复合以及缓慢的OER动力学等因素,导致BiVO4的PEC性能受到严重限制.本文开发了一种新颖有效的解决方案,以低成本、高电导率和具有快速电荷转移能力的硫化钴装饰来提升BiVO4光阳极的PEC活性,X射线多晶衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等表征,研究结果表明CoS成功装饰于BiVO4表面.采用紫外-可见吸收光谱(UV-VisDRS)研究了BiVO4和复合光阳极CoS/BiVO4的光学性质,结果表明,与纯的BiVO4相比,CoS/BiVO4光阳极在可见光范围内光吸收能力有所增强.将制备的BiVO4和CoS/BiVO4光阳极应用于PEC分解水实验中,结果表明,相对于1.23 V可逆氢电极,在光照下,CoS/BiVO4光阳极的光电流密度显著提升,可高达3.2 m Acm-2,是纯BiVO4的2.5倍以上.与纯BiVO4相比,CoS/BiVO4光阳极的起始氧化电位显示出负向偏移0.2 V,表明析氧过电势得到有效减小.入射光子转换效率(IPCE)测试结果表明,CoS/BiVO4光阳极的入射光子转换效率在500 nm之前的可见光范围内得到明显提升,其中,CoS/BiVO4的IPCE值在380 nm处达到最大.此外,由于CoS的装饰作用,CoS/BiVO4光阳极的电荷注入效率和电荷分离效率均得到较大的提升,分别达到75.8%(相较于纯BiVO4光阳极的36.7%)和79.8%(相较于纯BiVO4光阳极的66.8%).电化学阻抗谱(EIS)测试结果表明,通过CoS的装饰,CoS/BiVO4光阳极的界面电荷转移电阻得到有效降低,证明其界面电荷转移动力学得到有效提升.光致发光光谱测试结果表明,CoS的装饰显著提高了BiVO4的光生电子-空穴对的分离效率,进一步证明BiVO4表面的CoS装饰在其PEC分解水中起着非常积极的作用.本文为通过表面修饰设计应用于PEC水分解的有效的光阳极提供了新思路.  相似文献   
10.
Circulating tumor cells (CTCs) have been proven to have significant prognostic, diagnostic, and clinical values in early-stage cancer detection and treatment. The efficient separation of CTCs from peripheral blood can ensure intact and viable CTCs and can, thus, give proper genetic characterization and drug innovation. In this study, continuous and high-throughput separation of MDA-231 CTCs from overlapping sized white blood cells (WBCs) is achieved by modifying inertial cell focusing with dielectrophoresis (DEP) in a single-stage microfluidic platform by numeric simulation. The DEP is enabled by embedding interdigitated electrodes with alternating field control on a serpentine microchannel to avoid creating two-stage separation. Rather than using the electrokinetic migration of cells which slows down the throughput, the system leverages the inertial microfluidic flow to achieve high-speed continuous separation. The cell migration and cell positioning characteristics are quantified through coupled physics analyses to evaluate the effects of the applied voltages and Reynolds numbers (Re) on the separation performance. The results indicate that the introduction of DEP successfully migrates WBCs away from CTCs and that separation of MDA-231 CTCs from similar sized WBCs at a high Re of 100 can be achieved with a low voltage of magnitude 4 ×106 V/m. Additionally, the viability of MDA-231 CTCs is expected to be sustained after separation due to the short-term DEP exposure. The developed technique could be exploited to design active microchips for high-throughput separation of mixed cell beads despite their significant size overlap, using DEP-modified inertial focusing controlled simply by adjusting the applied external field.  相似文献   
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