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81.
82.
Fares Zouaoui Nadia Zine Abdelhamid Errachid Nicole Jaffrezic-Renault 《Electroanalysis》2022,34(7):1131-1140
In this article, a mathematical model was developed to describe and optimize the configuration of the urea biosensor. The biosensor is based on interdigitated gold microelectrodes modified with a urease enzyme membrane. The model presented here focuses on the enzymatic reaction and/or diffusion phenomena that occur in the enzyme membrane and in the diffusion layer. Numerical resolution of differential equations was performed using the finite difference technique. The mathematical model was validated using experimental biosensor data. The responses of the biosensor to various conditions were simulated to guide experiments, improve analytical performance, and reduce development costs. 相似文献
83.
Dr. Anna R. Ziefuss Michael Willeke Matthias Miertz Dr. Alexander Heinemann Dr. Christoph Rehbock Prof. Dr. Stephan Barcikowski 《Chemphyschem》2022,23(10):e202200033
Noble metal alloy nanoclusters (NCs) are interesting systems as the properties of two or more elements can be combined in one particle, leading to interesting fluorescence phenomena. However, previous studies have been exclusively performed on ligand-capped NCs from wet chemical synthesis. This makes it difficult to differentiate to which extent the fluorescence is affected by ligand-induced effects or the elemental composition of the metal core. In this work, we used laser fragmentation in liquids (LFL) to fabricate colloidal gold-rich bi-metallic AuPt NCs in the absence of organic ligands and demonstrate the suitability of this technique to produce molar fraction series of 1nm alloy NC. We found that photoluminescence of ligand-free NCs is not a phenomenon limited to Au. However, even minute amounts of Pt atoms in the AuPt NCs lead to quenching and red-shift of the fluorescence, which may be attributed to the altered surface charge density. 相似文献
84.
85.
From the early precipitation-based techniques, introduced more than a century ago, to the latest development of enzymatic bio- and nano-sensor applications, the analysis of phytic acid and/or other inositol phosphates has never been a straightforward analytical task. Due to the biomedical importance, such as antinutritional, antioxidant and anticancer effects, several types of methodologies were investigated over the years to develop a reliable determination of these intriguing analytes in many types of biological samples; from various foodstuffs to living cell organisms. The main aim of the present work was to critically overview the development of the most relevant analytical principles, separation and detection methods that have been applied in order to overcome the difficulties with specific chemical properties of inositol phosphates, their interferences, absence of characteristic signal (e.g., absorbance), and strong binding interactions with (multivalent) metals and other biological molecules present in the sample matrix. A systematical and chronological review of the applied methodology and the detection system is given, ranging from the very beginnings of the classical gravimetric and titrimetric analysis, through the potentiometric titrations, chromatographic and electrophoretic separation techniques, to the use of spectroscopic methods and of the recently reported fluorescence and voltammetric bio- and nano-sensors. 相似文献
86.
近年来,微流控纸芯片由于低成本、便携化、检测快等优点,在需要快速检测的环境分析领域中展现出了巨大的应用前景。该综述从微流控纸芯片在环境分析中的应用角度,总结归纳了微流控纸芯片在环境分析中的最新研究进展,并展望了其在未来的发展趋势与挑战。论文内容引用150余篇源于科学引文索引(SCI)与中文核心期刊中的相关论文。该综述包括微流控纸芯片在环境检测中的优势与制造方法介绍;电化学法、荧光法、比色法、表面增强拉曼法、集成传感法等基于纸芯片的先进分析方法介绍;根据环境分析目标物种类,如重金属离子、营养盐、农药、微生物、抗生素以及其他污染物等,对纸芯片的最新应用现状进行了举例评述;基于微流控纸芯片的环境分析研究的未来发展趋势和前景展望。通过综述近期相关研究,表明微流控纸芯片从提出至今虽然只有十几年的发展历程,但其在环境分析研究中的发展却十分迅速。微流控纸芯片可以根据不同的环境条件和检测要求灵活选择制作与分析方法,实现最佳的检测效果。但是微流控纸芯片也面临一些挑战,如纸张机械强度不足、流体控制程度不佳等问题。这些问题指出了微流控纸芯片在环境检测领域的发展趋势,相信随着不断深入的研究,纸芯片将会在未来的环境分析中发挥更大作用。 相似文献
87.
首先对空空导弹测试系统应用各种仪器总线的情况进行了分析研究,然后介绍了一台PXI总线测试设备的改造方案,该方案中设计了一套基于LXI总线控制的电源子系统,该子系统与PXI主系统一起形成了新的混合总线控制测试设备。该改造方案实现了改造需求中的低成本和小型化设计。同时,结合该方案分析了LXI总线在空空导弹测试系统上应用的优缺点和现阶段局限性。提出了空空导弹测试系统应向着通用、开放和网络化方向发展的观点,得出了未来的空空导弹测试系统将是包含GPIB、VXI、PXI、LXI等总线接口的合成系统,各总线接口仅是网络上的一个节点的结论。 相似文献
88.
Design of Ratiometric Fluorescent Probes Based on Arene–Metal‐Ion Interactions and Their Application to CdII and Hydrogen Sulfide Imaging in Living Cells 下载免费PDF全文
Ippei Takashima Miyuki Kinoshita Ryosuke Kawagoe Saika Nakagawa Prof. Dr. Manabu Sugimoto Prof. Dr. Itaru Hamachi Prof. Dr. Akio Ojida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2184-2192
Non‐coordinative interactions between a metal ion and the aromatic ring of a fluorophore can act as a versatile sensing mechanism for the detection of metal ions with a large emission change of fluorophores. We report the design of fluorescent probes based on arene–metal‐ion interactions and their biological applications. This study found that various probes having different fluorophores and metal binding units displayed significant emission redshift upon complexation with metal ions, such as AgI, CdII, HgII, and PbII. X‐ray crystallography of the complexes confirmed that the metal ions were held in close proximity to the fluorophore to form an arene–metal‐ion interaction. Electronic structure calculations based on TDDFT offered a theoretical basis for the sensing mechanism, thus showing that metal ions electrostatically modulate the energy levels of the molecular orbitals of the fluorophore. A fluorescent probe was successfully applied to the ratiometric detection of the uptake of CdII ions and hydrogen sulfide (H2S) in living cells. These results highlight the utility of interactions between arene groups and metal ions in biological analyses. 相似文献
89.
Polydimethylsiloxane: A General Matrix for High‐Performance Chromatographic NMR Spectroscopy 下载免费PDF全文
Dr. Shaohua Huang Dr. Jun Gao Rui Wu Prof. Dr. Shengying Li Prof. Dr. Zhengwu Bai 《Angewandte Chemie (International ed. in English)》2014,53(43):11592-11595
The detection and structural characterization of the components of a mixture is a challenging task. Therefore, the development of a facile and general method that enables both the separation and the structural characterization of the components is desired. Diffusion‐ordered NMR spectroscopy (DOSY) with the aid of a matrix is a promising tool for this purpose. However, because the currently existing matrices only separate limited components, the application of the DOSY technique is restricted. Herein we introduce a new versatile matrix, poly(dimethylsiloxane), which can fully separate many mixtures of different structural types by liquid‐state NMR spectroscopy. With poly(dimethylsiloxane), liquid‐state chromatographic NMR spectroscopy could become a general approach for the structural elucidation of mixtures of compounds. 相似文献
90.
How Many Molecules are Required to Obtain a Steady Faradaic Current from Mediated Electron Transfer at a Single Nanoparticle on a Supporting Surface? 下载免费PDF全文
Enno Kätelhön Kay J. Krause Prof. Dr. Bernhard Wolfrum Prof. Dr. Richard G. Compton 《Chemphyschem》2014,15(5):872-875
We investigate the chronoamperometric noise characteristics of electron‐transfer reactions occurring on single nanoparticles (NPs) and assemblies of well‐separated NPs on a supporting surface. To this end, we combine a formerly described expression for the steady‐state current of a single particle with the shot‐noise model and derive an expression for the signal‐to‐noise ratio as a function of bulk concentration and particle radius. Our findings are supported by random‐walk simulations, which closely match the analytical results. 相似文献