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951.
Holger Klein Ralf Mietchen Helmut Reinke Manfred Michalik 《Advanced Synthesis \u0026amp; Catalysis》1999,341(1):41-46
A convenient method is reported to generate the ortho-pivalic acid esters 5 and 7 from meso-erythrit 3 ) and D -mannitol ( 6 ), respectively, using a HF-supported procedure. Furthermore, the α-D -glucopyrano[1,2-d]-2-oxazolines 9 and 10 were prepared from starch and nitriles (pivalonitrile and benzonitrile) by a Ritter-type reaction in anhydrous hydrogen fluoride. The separation of the products 5 , 7 , 9 , and 10 was possible by quenching of their HF-solutions with triethylamine. The structure of the orthoester 7 and the oxazoline 10 was confirmed by X-ray analyses. 相似文献
952.
Hans Bock Holger Schdel T. T. Han Van Rüdiger Dienelt Matthias Gluth 《Advanced Synthesis \u0026amp; Catalysis》1998,340(8):722-732
Interactions in Crystals. 136. Protonated Dipyridylamine Salts with Different Anions: Monomeric Tetraphenylborate as well as Bis(trifluormethylsulfonate), Dimeric Squarate and Polymeric Chloride Dihydrate Di(pyrid-2-yl)amine is monoprotonated by acetic, squaric as well as hydrochloric acid and diprotonated by trifluoromethylsulfonic acid. To explore the anion and hydrogen-bridge dependency of its salts, crystals of the monomeric tetraphenylborate, the dimeric squarate as well as the bis(trifluoromethylsulfonate) and the polymeric chloride hydrate have been grown and their structures determined: Separated by bulky tetraphenylborate anions, pyrid-2-yl(2′-pyridinium) amine cation contains an intramolecular hydrogen bridge N⊕H…︁N and is slightly folded. The squarate salt dimer exhibits additional bridges, N H…︁O⊖ and O H…︁O. The severely twisted di(2-pyridinium)amine dication is connected to its trifluormethylsulfonate counter anions by altogether three H-bridges, two N⊕H…︁O and one N H…︁O. The chloride dihydrate crystallizes in layers of 16-membered rings, formed from three Cl anions and five water molecules. The diversity of the hydrogen-bridge dominated salt structures is discussed based on comparison with selected literature examples and on PM3 calculations. 相似文献
953.
Novel families of thermoplastic polysaccharides such as cellulose-2,5-acetate were produced by means of reactive processing technology that grafted cyclic lactones simultaneously onto polysaccharide, hydroxyfunctional plasticizer, and optionally also onto hydroxyfunctional fillers. Organosolv lignin, cellulose, starch, and chitin were added to effect reinforcement of the polymer matrix. Mechanical and thermal properties depended upon molecular architecture of the components and process parameters such as temperature, feed ratios, and screw speed. Such blends and composites utilize renewable resources and are of interest in waste disposal via biodegradation. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 213–242, 1997 相似文献
954.
Holger Eggemann 《Stahlbau》2004,73(4):282-282
955.
Xing Yi Ling In Yee Phang Holger Schönherr David N. Reinhoudt G. Julius Vancso Jurriaan Huskens 《Small (Weinheim an der Bergstrasse, Germany)》2009,5(12):1428-1435
Freestanding particle bridges with controlled composition and macroscopic robustness are demonstrated by the use of supramolecular nanoparticle assembly. Self‐assembly of nanoparticles, templating, and supramolecular glue infiltration are combined to form stable and ordered three‐dimensional polystyrene particle composites on a polydimethylsiloxane stamp. Freestanding hybrid polystyrene nanoparticle bridges are obtained by transfer printing of the hybrid structures onto topographically patterned substrates via host–guest interactions. The mechanical robustness and rigidity of the particle bridges can be controlled by manipulating the layer‐by‐layer cycles of supramolecular glues of gold nanoparticles and dendrimers. Atomic force microscopy‐based microbending results, in particular the location and force‐dependent deflection behavior, confirm that the particle bridge fulfills the classical supported‐beam characteristics. As estimated from classical beam theory, the bending moduli of the particle bridges vary between 0.8 and 1.1 GPa, depending on the degree of filling by the supramolecular glues. Failure analysis on the particle structure indicates linear elastic behavior and a plastic deformation upon failure. 相似文献
956.
通过对掩模衬底材料和掩模加工工艺利用硬性分界条件可满足45nm及以下技术节点的掩模要求。此外类似于折射指数、平整度、成分、均匀性和应力等衬底材料的固有特性严重地影响到掩模加工性能和光刻性能。评述了45nm及以下技术节点对空白材料,掩模及晶片层面的要求。指出了对于关键问题及出现的问题的可仿效实施的方法,最后研究了集成用于高效光掩模工厂的掩模材料的实际情况分析。 相似文献
957.
958.
According to investigations conducted on the median fiber length, mass‐specific energy consumption, Young modulus and minimal content of epoxy adhesion, the extraction of free carbon fibers from carbon fiber reinforced polymers by electrohydraulic fragmentation can be considered as downcycling. This means that the gained secondary raw material has a lower product quality than the virgin material and the energy required for its production is higher than for the virgin fibers. 相似文献
959.
960.
Heiko Frenzel Alexander Lajn Holger von Wenckstern Michael Lorenz Friedrich Schein Zhipeng Zhang Marius Grundmann 《Advanced materials (Deerfield Beach, Fla.)》2010,22(47):5323-5323
Metal‐semiconductor field‐effect transistors (MESFETs) are widely known from opaque high‐speed GaAs or high‐power SiC and GaN technology. For the emerging field of transparent electronics, only metal‐insulator‐semiconductor field‐effect transistors (MISFETs) were considered so far. This article reviews the progress of high‐performance MESFETs in oxide electronics and reflects the recent advances of this technique towards transparent MESFET circuitry. We discuss design prospects as well as limitations regarding device performance, reliability and stability. The presented ZnO‐based MESFETs and inverters have superior properties compared to MISFETs, i.e., high channel mobilities and on/off‐ratios, high gain, and low uncertainty level at comparatively low operating voltages. This makes them a promising approach for future low‐cost transparent electronics. 相似文献