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891.
892.
Structure of an antioxidant from fermented soybeans (tempeh) 总被引:7,自引:0,他引:7
Markus B. Hoppe Hem Chandra Jha Heinz Egge 《Journal of the American Oil Chemists' Society》1997,74(4):477-479
In an exhaustive investigation of the antioxidative properties of tempeh constituents, the substance at R
f
0.58 (cyclohexane/ethyl ether, 9:1) was isolated and purified. Until now, only the ultraviolet and fluorescence data of the
substance were known, and the presence of an OH group was indicated. In the present paper, the structure of the substance
at R
f
0.58 was elucidated by the application of spectroscopic methods and found to be 5-(δ-tocopheroxy)-δ-tocopherol. That previous
researchers did not confirm antioxidant activity in tempeh oil has been related to the way the tempeh oil was prepared. Previous
suggestions regarding the substance at R
f
0.58 as being one of the main tempeh antioxidants could not be proved. The antioxidative effect of tempeh oil seems to be
the result of a synergistic effect of tocopherols (present in the soybeans) and amino acids (liberated during the fermentation
process with Rhizopus oligosporus). 相似文献
893.
Rene Gutmann Sylvia Eller Markus Fessler Wytze E. van der Veer Alexander Dumfort Holger Kopacka Thomas Müller Peter Brüggeller 《Inorganic chemistry communications》2007,10(12):1510-1514
For the first time the excited states of the RuP2N4 moiety belonging to a new heterodimetallic OsII–RuII bipyridyl complex are successfully designed in order to introduce photochemical reactivity. This dramatic effect is achieved via the use of the sterically demanding bis(bidentate) phosphine cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb). Thus, the temperature dependence of the luminescence lifetimes ranging from 77 to 298 K for the novel homodimetallic species meso-(ΔΛ/ΛΔ)-[Os2(dppcb)(bpy)4](PF6)4 (1) and rac-(ΔΔ/ΛΛ)-[Os2(dppcb)(bpy)4](PF6)4 (2) clearly indicates that the d–d state responsible for photochemistry is not populated. By contrast, the analogous temperature dependence for the new heterodimetallic species ΔΛ/ΛΔ-[Os(bpy)2(dppcb)Ru(bpy)2](PF6)4 (3) and ΔΔ/ΛΛ-[Os(bpy)2(dppcb)Ru(bpy)2](PF6)4 (4) unequivocally shows that as a consequence of the population of the d–d state the photochemical reactivity is switched on. Since single crystal X-ray structure analyses are a major clue to the understanding of photophysical and photochemical properties, also the X-ray structures of 1–3 are given. 相似文献
894.
There are great efforts in developing effective composite structures for lightweight constructions for nearly every field of engineering. This concerns for example aeronautics, but also automotive industry and energy harvesting applications. Modern concepts of lightweight components try to use structures with adjustable properties. However, classic composite materials can only slightly adapt to varying environmental conditions because most materials, like carbon- or glass-fiber composites, show properties which are time-constant and not changeable. This contribution describes the development, the potential and the limitations of novel smart, self-controlling structures which can change their mechanical properties—in particular their flexural stiffness—by more than one order of magnitude. These structures use a multi-layer approach consisting of a ten-layer stack of 0.75 mm thick polycarbonate layers. The set-up is analytically described and its mechanical behavior is predicted by finite element analysis performed with ABAQUS. The individual layers are braided together by an array of shape memory alloy wires, which can be activated either all together or independently. Depending on the temperature applied by an electrical current flowing through the wires and the corresponding contraction, the wires can control the area moment of inertia of the whole stack, and with it the bending stiffness. First experimental investigations have shown a maximum stiffness change by a factor of 60, which is close to the theoretically predicted value. 相似文献
895.
896.
Reto Tschan Markus M. Schubert Alfons Baiker Werner Bonrath Hans Lansink-Rotgerink 《Catalysis Letters》2001,74(1-2):31-36
A novel catalyst, Ni/Ce–ZrO2, exhibits very high catalytic activity and stability even in the stoichiometric steam reforming of methane (H2O/CH4 = 1). Furthermore, when it was employed in oxy-steam reforming, it gave enhanced CH4 conversion (99.1%) at 750°C and the activity was maintained for 100 h. The high catalyst stability is mainly ascribed to the synergistic effect of the Ce modifier resulting from high capacity to store oxygen and high ability to produce mobile oxygen. 相似文献
897.
In this paper, we identify the problems of current semantic and hybrid search systems, which seek to bridge structure and unstructured data, and propose solutions. We introduce a novel input mechanism for hybrid semantic search that combines the clean and concise input mechanisms of keyword-based search engines with the expressiveness of the input mechanisms provided by semantic search engines. This interactive input mechanism can be used to formulate ontology-aware search queries without prior knowledge of the ontology. Furthermore, we propose a system architecture for automatically fetching relevant unstructured data, complementing structured data stored in a Knowledge Base, to create a combined index. This combined index can be used to conduct hybrid semantic searches which leverage information from structured and unstructured sources. We present the reference implementation Hybrid Semantic Search System ( \(HS^3\) ), which uses the combined index to put hybrid semantic search into practice and implements the interactive ontology-enhanced keyword-based input mechanism. For demonstration purpose, we apply \(HS^3\) to the tourism domain. We present performance test results and the results of a user evaluation. Finally, we provide instructions on how to apply \(HS^3\) to arbitrary domains. 相似文献
898.
Markus Eich Francisco Bonnin‐Pascual Emilio Garcia‐Fidalgo Alberto Ortiz Gabriele Bruzzone Yannis Koveos Frank Kirchner 《野外机器人技术杂志》2014,31(2):319-341
Seagoing vessels have to undergo regular inspections, which are currently performed manually by ship surveyors. The main cost factor in a ship inspection is to provide access to the different areas of the ship, since the surveyor has to be close to the inspected parts, usually within arm's reach, either to perform a visual analysis or to take thickness measurements. The access to the structural elements in cargo holds, e.g., bulkheads, is normally provided by staging or by “cherry‐picking” cranes. To make ship inspections safer and more cost‐efficient, we have introduced new inspection methods, tools, and systems, which have been evaluated in field trials, particularly focusing on cargo holds. More precisely, two magnetic climbing robots and a micro‐aerial vehicle, which are able to assist the surveyor during the inspection, are introduced. Since localization of inspection data is mandatory for the surveyor, we also introduce an external localization system that has been verified in field trials, using a climbing inspection robot. Furthermore, the inspection data collected by the robotic systems are organized and handled by a spatial content management system that enables us to compare the inspection data of one survey with those from another, as well as to document the ship inspection when the robot team is used. Image‐based defect detection is addressed by proposing an integrated solution for detecting corrosion and cracks. The systems' performance is reported, as well as conclusions on their usability, all in accordance with the output of field trials performed onboard two different vessels under real inspection conditions. 相似文献
899.
Warnke U Rappel C Meier H Kloft C Galanski M Hartinger CG Keppler BK Jaehde U 《Chembiochem : a European journal of chemical biology》2004,5(11):1543-1549
DNA is the ultimate target of platinum-based anticancer therapy. Since the N7 of guanine is known to be the major binding site of cisplatin and its analogues, adduct formation with model nucleotides, especially 2'-deoxyguanosine 5'-monophosphate (dGMP), has been studied in detail. During the last few years a coupled capillary eletrophoresis/electrospray-ionization mass spectrometry (CE/ESI-MS) method has been advantageously used in order to separate and identify platinum adducts with nucleotides in submillimolar concentrations in aqueous solutions. Beside the bisadduct, [Pt(NH(3))(2)(dNMP)(2)](2-) (NMP=2'-deoxynucleoside 5'-monophosphate), and the well-known monochloro and monohydroxo adducts, [Pt(NH(3))(2)Cl(dNMP)](-) and [Pt(NH(3))(2)(dNMP)OH](-), respectively, a third kind of monoadduct species with a composition of [Pt(NH(3))(2)(dNMP)](-) can be separated by CE and detected through the m/z values measured with ESI-MS. Different experimental setups indicate the existence of an O(6)-N7 chelate, whereas the formation of N7-alphaPO(4) macrochelates or dinuclear species is unlikely. Additionally, offline MS experiments with 2'-deoxyguanosine (dG) and stabilization of the controversially discussed O(6)-N7 chelate by oxidation with hydrogen peroxide support the assumption of the existence of O(6)-N7 chelation. 相似文献
900.
Through 16 problem-focused interviews in three German surgical clinics, anxieties that affect the adoption of ambient intelligence in healthcare were investigated. This research reveals 17 anxieties, grouped into 5 categories containing implementation anxieties of ambient intelligence in hospitals. The results expand the basis in theory underlying technology-related anxieties of medical professionals and offer theoretical and practical implications, leading to an initial basis for decisions regarding the implementation of ambient systems. 相似文献