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排序方式: 共有489条查询结果,搜索用时 15 毫秒
481.
Chong Wang Yanan Wang Xinghua Su Viktor G. Hadjiev Shenyu Dai Zhaojun Qin Hector A. Calderon Benavides Yizhou Ni Qiang Li Jie Jian Md. Kamrul Alam Haiyan Wang Francisco C. Robles Hernandez Yan Yao Shuo Chen Qingkai Yu Guoying Feng Zhiming Wang Jiming Bao 《Advanced materials (Deerfield Beach, Fla.)》2019,31(33)
Since the first report of the green emission of 2D all‐inorganic CsPb2Br5, its bandgap and photoluminescence (PL) origin have generated intense debate and remained controversial. After the discovery that PL centers occupy only specific morphological structures in CsPb2Br5, a two‐step highly sensitive and noninvasive optical technique is employed to resolve the controversy. Same‐spot Raman‐PL as a static property–structure probe reveals that CsPbBr3 nanocrystals are contributing to the green emission of CsPb2Br5; pressure‐dependent Raman‐PL with a diamond anvil cell as a dynamic probe further rules out point defects such as Br vacancies as an alternative mechanism. Optical absorption under hydrostatic pressure shows that the bandgap of CsPb2Br5 is 0.3–0.4 eV higher than previously reported values and remains nearly constant with pressure up to 2 GPa in good agreement with full‐fledged density functional theory (DFT) calculations. Using ion exchange of Br with Cl and I, it is further proved that CsPbBr3?x Xx (X = Cl or I) is responsible for the strong visible PL in CsPb2Br5?x Xx . This experimental approach is applicable to all PL‐active materials to distinguish intrinsic defects from extrinsic nanocrystals, and the findings pave the way for new design and development of highly efficient optoelectronic devices based on all‐inorganic lead halides. 相似文献
482.
483.
Wireless sensor networks (WSNs) are typically constituted by a large number of connected wireless sensors (nodes), generally distributed at random on a given surface area. In such large-scale networks, the desired global system performance is achieved by gathering local information and decisions collected from each individual node. There exist two fundamental global issues on WSNs that we consider here, i.e. full network connectivity and network lifetime. Full connectivity can be obtained either by increasing transmission range, at the expense of consuming higher transmission power, or by increasing the number of sensors, i.e. by increasing network costs. Both of them are closely related to global network lifetime, in the sense that the higher the power consumption or the more sensors deployed the shorter the network lifetime [31]. So the main question is, how can one design large-scale random networks in order to have both global connectivity and maximum network lifetime? Although these questions have been addressed often in the past, a definite, simple predicting algorithm for achieving these goals does not exist so far. In this paper, we aim to discuss such a scheme and confront it with extensive simulations of random networks generated numerically. Specifically, we study the minimum number of nodes required to achieve full network connectivity, and present an analytical formula for estimating it. The results are in very good agreement with the numerical simulations as a function of transmission range. In addition, we study in detail several other statistical properties of large-scale WSNs, such as average path distance, clustering coefficient, degree distribution, etc., also as a function of the transmission range, both qualitatively and quantitatively. We discuss results on how to further improve network energy consumption from the original networks considered by switching off (deleting) some nodes at random but keeping whole network connectivity. The present results are expected to be useful for the design of more efficient large-scale WSNs. 相似文献
484.
485.
Jacqueline A. Treat Ryan Pfeiffer Hector Barajas-Martinez Robert J. Goodrow Corina Bot Rodolfo J. Haedo Ronald Knox Jonathan M. Cordeiro 《International journal of molecular sciences》2021,22(13)
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are used for genetic models of cardiac diseases. We report an arrhythmia syndrome consisting of Early Repolarization Syndrome (ERS) and Short QT Syndrome (SQTS). The index patient (MMRL1215) developed arrhythmia-mediated syncope after electrocution and was found to carry six mutations. Functional alterations resulting from these mutations were examined in patient-derived hiPSC-CMs. Electrophysiological recordings were made in hiPSC-CMs from MMRL1215 and healthy controls. ECG analysis of the index patient showed slurring of the QRS complex and QTc = 326 ms. Action potential (AP) recordings from MMRL1215 myocytes showed slower spontaneous activity and AP duration was shorter. Field potential recordings from MMRL1215 hiPSC-CMs lack a “pseudo” QRS complex suggesting reduced inward current(s). Voltage clamp analysis of ICa showed no difference in the magnitude of current. Measurements of INa reveal a 60% reduction in INa density in MMRL1215 hiPSC-CMs. Steady inactivation and recovery of INa was unaffected. mRNA analysis revealed ANK2 and SCN5A are significantly reduced in hiPSC-CM derived from MMRL1215, consistent with electrophysiological recordings. The polygenic cause of ERS/SQTS phenotype is likely due to a loss of INa due to a mutation in PKP2 coupled with and a gain of function in IK,ATP due to a mutation in ABCC9. 相似文献
486.
Hector Ortega-Arranz Yuri Torres Arturo Gonzalez-Escribano Diego R. Llanos 《The Journal of supercomputing》2014,70(2):786-798
During the last years, GPU manycore devices have demonstrated their usefulness to accelerate computationally intensive problems. Although arriving at a parallelization of a highly parallel algorithm is an affordable task, the optimization of GPU codes is a challenging activity. The main reason for this is the number of parameters, programming choices, and tuning techniques available, many of them related with complex and sometimes hidden architecture details. A useful strategy to systematically attack these optimization problems is to characterize the different kernels of the application, and use this knowledge to select appropriate configuration parameters. The All-Pair Shortest-Path (APSP) problem is a well-known problem in graph theory whose objective is to find the shortest paths between any pairs of nodes in a graph. This problem can be solved by highly parallel and computational intensive tasks, being a good candidate to be exploited by manycore devices. In this paper, we use kernel characterization criteria to optimize an APSP algorithm implementation for NVIDIA GPUs. Our experimental results show that the combined use of proper configuration policies, and the concurrent kernels capability of new CUDA architectures, leads to a performance improvement of up to 62 % with respect to one of the possible configurations recommended by CUDA, considered as baseline. 相似文献
487.
Rader Katherine E. Carter Jon T. Hector Louis G. Taleff Eric M. 《Metallurgical and Materials Transactions A》2021,52(9):4003-4017
Metallurgical and Materials Transactions A - A warm forming process with a simultaneous retrogression heat treatment, termed retrogression forming, can achieve good formability in high-strength... 相似文献
488.
In vitro removal of ochratoxin A by wine lactic acid bacteria 总被引:1,自引:0,他引:1
Del Prete V Rodriguez H Carrascosa AV de las Rivas B Garcia-Moruno E Muñoz R 《Journal of food protection》2007,70(9):2155-2160
A study was carried out to determine the in vitro interaction between ochratoxin A (OTA) and wine lactic acid bacteria (LAB). Fifteen strains belonging to five relevant oenological LAB species were grown in liquid synthetic culture medium containing OTA. The portion of OTA removed during the bacterial growth was 8 to 28%. The OTA removed from the supernatants was partially recovered (31 to 57%) from the bacterial pellet. Cell-free extracts of three representative strains were produced by disrupting cells in a French pressure cell. The ability of crude cell-free extracts to degrade OTA was studied. OTA was not degraded by cell-free extracts of wine LAB strains, and no degradation products of OTA were detected in the high-performance liquid chromatograms of the methanol extract of the bacterial pellet. On the basis of these results, we conclude that OTA removal by wine LAB is a cell-binding phenomenon. The chemistry and the molecular basis of OTA binding to wine LAB remains unknown. 相似文献
489.
Achieving integrated river basin management in large multi-jurisdictional river basins is a difficult task. In the Mekong River basin some of the countries have begun to implement a cooperative framework, which indicates a desire to achieve a form of integrated management. Significant progress has been made but results still fall short of the ideal. The primary reasons for this includes the lack of institutional capacity of the multi-jurisdictional cooperative authority and its counterpart organizations in each of the participating countries, together with a lack of political drive to develop integrated management as a priority. 相似文献