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排序方式: 共有734条查询结果,搜索用时 15 毫秒
721.
Michael Remmel Lukas Scheiderer Alexey N. Butkevich Mariano L. Bossi Stefan W. Hell 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(12):2206026
The introduction of MINFLUX nanoscopy allows single molecules to be localized with one nanometer precision in as little as one millisecond. However, current applications have so far focused on increasing this precision by optimizing photon collection, rather than minimizing the localization time. Concurrently, commonly used fluorescent switches are specifically designed for stochastic methods (e.g., STORM), optimized for a high photon yield and rather long on-times (tens of milliseconds). Here, accelerated MINFLUX nanoscopy with up to a 30-fold gain in localization speed is presented. The improvement is attained by designing spontaneously blinking fluorescent markers with remarkably fast on-times, down to 1–3 ms, matching the iterative localization process used in a MINFLUX microscope. This design utilizes a silicon rhodamine amide core, shifting the spirocyclization equilibrium toward an uncharged closed form at physiological conditions and imparting intact live cell permeability, modified with a fused (benzo)thiophene spirolactam fragment. The best candidate for MINFLUX microscopy (also suitable for STORM imaging) is selected through detailed characterization of the blinking behavior of single fluorophores, bound to different protein tags. Finally, optimization of the localization routines, customized to the fast blinking times, renders a significant speed improvement on a commercial MINFLUX microscope. 相似文献
722.
Dr. Lukas Kahlert Dr. Michael S. Lichstrahl Prof. Dr. Craig A. Townsend 《Chembiochem : a European journal of chemical biology》2023,24(5):e202200668
Adenylation domains are the main contributor to structural complexity among nonribosomal peptides due to their varied but stringent substrate selection. Several in vitro assays to determine the substrate specificity of these dedicated biocatalysts have been implemented, but high sensitivity is often accompanied by the cost of laborious procedures, expensive reagents or the requirement for auxiliary enzymes. Here, we describe a simple protocol that is based on the removal of ferric iron from a preformed chromogenic complex between ferric iron and Chrome Azurol S. Adenylation activity can be rapidly followed by a decrease in absorbance at 630 nm, visualized by a prominent color change from blue to orange. 相似文献
723.
724.
Andreas Rosenauer Dominik Brandl Gerald Ressel Sarah Lukas Christian Gruber Martin Stockinger Ronald Schnitzer 《Advanced Engineering Materials》2023,25(12):2300410
The standard heat treatment of PH 13-8 Mo maraging steels consists of solution annealing and subsequent aging. Herein, it is investigated how an additional intercritical annealing step prior to aging affects the microstructure, and, consequently, the mechanical properties of a PH 13-8 Mo maraging steel. In situ techniques by means of high-temperature electron backscatter diffraction and high-temperature X-ray diffraction are applied to study the microstructural changes during intercritical annealing and subsequent aging. In addition, high-resolution investigation methods, such as transmission electron microscopy and atom probe tomography supplemented by transmission Kikuchi diffraction, are used for an in-depth characterization of the microstructure. The results reveal that a diffusion-controlled martensite to austenite transformation accompanied by partitioning of the substitutional atoms Cr, Ni, and Mo takes place during intercritical annealing. As a result of partitioning during intercritical annealing, an inhomogeneous distribution of Ni remains in the microstructure after the martensitic transformation. Consequently, the formation of reverted austenite is facilitated during subsequent aging due to existing Ni-enriched zones in martensite. Since the fracture toughness is significantly enhanced compared to the standard heat treatment, it is suggested that this improvement is related to the increased phase fraction of reverted austenite. 相似文献
725.
Amelie Merkel Lukas Plessing Prof. Dr. Gerrit A. Luinstra Prof. Dr.-Ing. Marcus Grünewald Dr.-Ing. Philip Biessey 《化学,工程师,技术》2023,95(8):1323-1331
This work addresses the processing of a polystyrene recyclate stream into polystyrene synthesis on an industrial scale. Evaluating the energetic demand of the separation process with the following reintegration of the recyclate stream shows a significantly reduced specific energy input compared to conventional polystyrene synthesis. Therefore, recycling polystyrene by pyrolysis and thermal separation shows a considerable potential as a tool for industrial circular production in the plastics sector. 相似文献
726.
727.
Mykhailo Kondratiuk Dhyanesh Gopinath Asmaa Elrrays Lukas J. Gooßen 《European Journal of Lipid Science and Technology》2023,125(5):2200163
Unsaturated fatty acids are attractive alternatives to fossil-based materials as a source of hydrocarbons, but potential applications are limited by the preset chain length of 16–20 carbon atoms. However, if the double bond can be randomly moved along the chain, subsequent bond-breaking operations such as ethenolysis or oxidative cleavage will give rise to products with chain lengths ranging from 2 to 18 carbon atoms. A process for the double bond isomerization of rapeseed oil methyl esters in a flow-through reactor using zeolites as the catalyst is herein disclosed. Using H-mordenite as the catalyst at a flow of 0.125 mL min−1 at 290 °C, near equilibrium isomerization is reached with up to 49% recovery of linear monomeric products after 5 h and up to 44% after 48 h. The main side products are oligomers (3%–15%) and skeletal isomerization products (10%–23%). Practical applications: With a suitable follow-up modification addressing the double bond (metathesis, ozonolysis, oxidative cleavage), the product mixtures of double-bond positional isomers can be used in the production of short-chain base chemicals. In repetitive combination with metathesis catalysis, biofuels with customized chain length distributions can be generated. 相似文献
728.
Ayse Sünbül David Lehninger Raik Hoffmann Ricardo Olivo Aditya Prabhu Fred Schöne Kati Kühnel Moritz Döllgast Nora Haufe Lisa Roy Thomas Kämpfe Konrad Seidel Lukas M. Eng 《Advanced Engineering Materials》2023,25(4):2201124
Due to its ferroelectricity, hafnium oxide has attracted a lot of attention for ferroelectric memory devices. Amongst different dopant elements, zirconium is found to be beneficial due to the relatively low crystallization temperature of hafnium-zirconium-oxide (HZO), thus it is back-end-of-line (BEoL) compatible. The thickness of HZO has a significant impact on ferroelectric device reliability. High operation temperatures and high endurance are important criteria depending on the application. Herein, various HZO thicknesses (7, 8, and 10 nm) in MFM (metal-ferroelectric-metal) capacitors are investigated at varying operation temperatures (25 to 175 °C) at varying electric fields (±3 to ±5.4 MV cm−1) with respect to polarization, leakage current, endurance, and retention. 7 nm HZO showed promising results with an endurance of 107 cycles, with a low leakage current density, and almost no retention loss after 10 years. Extrapolated results at operation conditions (±2 MV cm−1 and 10 MHz) showed an endurance of 1010 cycles. 相似文献
729.
David Muoz‐Rojas Haiyan Sun Diana C. Iza Jonas Weickert Li Chen Haiyan Wang Lukas Schmidt‐Mende Judith L. MacManus‐Driscoll 《Progress in Photovoltaics: Research and Applications》2013,21(4):393-400
Ultrafast, spatial atmospheric atomic layer deposition, which does not involve vacuum steps and is compatible with roll‐to‐roll processing, is used to grow high quality TiO2 blocking layers for organic solar cells. Dense, uniform thin TiO2 films are grown at temperatures as low as 100 °C in only 37 s (~20 nm/min growth rate). Incorporation of these films in P3HT‐PCBM‐based solar cells shows performances comparable with cells made using TiO2 films deposited with much longer processing times and/or higher temperatures. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
730.
Engineered Platelet-Derived Growth Factor-Releasing Hydrogels Promote Fetal Membrane Healing In Vivo
Eva Avilla-Royo Ladina Vonzun Frauke Seehusen Queralt Vallmajo-Martin Flurina Famos Lukas Moser Katharina Gegenschatz-Schmid Lisa Amanda Krattiger Nele Strübing Miriam Weisskopf Ueli Moehrlen Nicole Ochsenbein-Kölble Martin Ehrbar 《Advanced functional materials》2023,33(9):2208910
Fetoscopic interventions to treat fetal anomalies are currently performed for a variety of conditions. Depending on the procedure, preterm rupture of the fetal membranes (FMs) happens in around 30% of the cases, potentially leading to preterm birth and fetal morbidity and mortality. Here, the capacity of modular transglutaminase crosslinked poly(ethylene glycol) (TG-PEG) hydrogels that release platelet-derived growth factor (PDGF)-BB to promote FM healing is described. In vitro, such growth factor-loaded hydrogels are able to stimulate amniotic cell migration and proliferation. When applied in vivo, these TG-PEG hydrogels tightly seal the FM and uterus defects created by a fetoscope and remain stable for 10 days. The migration of healing-related cells into such hydrogels in the myometrium, endometrium, and FM areas is only possible in soft TG-PEG hydrogels. Importantly, bioengineered hydrogels releasing PDGF-BB promote recruitment of host cells from the myometrium and the endometrium, and to a lesser extent from FM areas. In such hydrogels, the potent proliferation and matrix production of the recruited cells at the site of treatment into the biomaterial initiates a robust early healing response. PDGF-BB-loaded TG-PEG hydrogels hold great promise for the treatment of fetoscopy-induced FM defects and for the prevention of preterm birth. 相似文献