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排序方式: 共有293条查询结果,搜索用时 15 毫秒
61.
Hung Chi Chou Anas Mazady John Zeller Tariq Manzur Mehdi Anwar 《Journal of Electronic Materials》2013,42(5):882-888
A ZnO/Zn1?x Mg x O-based quantum cascade laser (QCL) is proposed as a candidate for generation of THz radiation at room temperature. The structural and material properties, field dependence of the THz lasing frequency, and generated power are reported for a resonant phonon ZnO/Zn0.95Mg0.05O QCL emitting at 5.27 THz. The theoretical results are compared with those from GaN/Al x Ga1?x N QCLs of similar geometry. Higher calculated optical output powers [ $ {P}_{\rm{ZnMgO}} $ = 2.89 mW (nonpolar) at 5.27 THz and 2.75 mW (polar) at 4.93 THz] are obtained with the ZnO/Zn0.95Mg0.05O structure as compared with GaN/Al0.05Ga0.95N QCLs [ $ {P}_{\rm{AlGaN}} $ = 2.37 mW (nonpolar) at 4.67 THz and 2.29 mW (polar) at 4.52 THz]. Furthermore, a higher wall-plug efficiency (WPE) is obtained for ZnO/ZnMgO QCLs [24.61% (nonpolar) and 23.12% (polar)] when compared with GaN/AlGaN structures [14.11% (nonpolar) and 13.87% (polar)]. These results show that ZnO/ZnMgO material is optimally suited for THz QCLs. 相似文献
62.
Kräß af Ekenstam R. Trendelenburg Zeller Frey-Wyssling M. Wolf G. Becker Liese Thienhaus Graf A. Troche A. v. Wacek O. Kratky M. Lüdtke Gustav G. Klem Schulz K. Storch Müller E. Becker Klauditz K. Nising A. Nowak L. Metz Egner Fessel Thiele Kraemer Lehnartz Kaiser Tiemann B. Thunell 《Holz als Roh- und Werkstoff》1940,3(11):383-393
Ohne Zusammenfassung 相似文献
63.
Chloride and Indium‐Chloride‐Complex Inorganic Ligands for Efficient Stabilization of Nanocrystals in Solution and Doping of Nanocrystal Solids
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Vladimir Sayevich Chris Guhrenz Maria Sin Volodymyr M. Dzhagan Alexander Weiz Daniel Kasemann Eike Brunner Michael Ruck Dietrich R. T. Zahn Karl Leo Nikolai Gaponik Alexander Eychmüller 《Advanced functional materials》2016,26(13):2163-2175
Here, the surface functionalization of CdSe and CdSe/CdS core/shell nanocrystals (NCs) with compact chloride and indium‐chloride‐complex ligands is reported. The ligands provide not only short interparticle distances but additionally control doping and passivation of surface trap states, leading to enhanced electronic coupling in NC‐based arrays. The solids based on these NCs show an excellent electronic transport behavior after heat treatment at the relatively low temperature of 190 °C. Indeed, the indium‐chlorido‐capped 4.5 nm CdSe NC based thin‐film field‐effect transistor reaches a saturation mobility of μ = 4.1 cm2 (V s)?1 accompanied by a low hysteresis, while retaining the typical features of strongly quantum confined semiconductor NCs. The capping with chloride ions preserves the high photoluminescence quantum yield ( ≈ 66%) of CdSe/CdS core/shell NCs even when the CdS shell is relatively thin (six monolayers). The simplicity of the chemical incorporation of chlorine and indium species via solution ligand exchange, the efficient electronic passivation of the NC surface, as well as their high stability as dispersions make these materials especially attractive for wide‐area solution‐processable fabrication of NC‐based devices. 相似文献
64.
When interacting with source control management system, developers often commit unrelated or loosely related code changes in a single transaction. When analyzing version histories, such tangled changes will make all changes to all modules appear related, possibly compromising the resulting analyses through noise and bias. In an investigation of five open-source Java projects, we found between 7 % and 20 % of all bug fixes to consist of multiple tangled changes. Using a multi-predictor approach to untangle changes, we show that on average at least 16.6 % of all source files are incorrectly associated with bug reports. These incorrect bug file associations seem to not significantly impact models classifying source files to have at least one bug or no bugs. But our experiments show that untangling tangled code changes can result in more accurate regression bug prediction models when compared to models trained and tested on tangled bug datasets—in our experiments, the statistically significant accuracy improvements lies between 5 % and 200 %. We recommend better change organization to limit the impact of tangled changes. 相似文献
65.
A Ployon F Lavaste N Maurel W Skalli J Dubousset R Zeller A Rolland Gosselin 《Canadian Metallurgical Quarterly》1997,83(8):719-729
PURPOSE: The aim of his study was to assess 3D global posture and movement of body segments, especially for scoliotic subjects. As scoliosis is a three-dimensional deformity, it needs three-dimensional evaluation and correction, but there is no mean today to get 3D dynamic examination of the whole body. MATERIAL AND METHODS: Using opto-electronic methods, an experimental protocol was established to compare the pre- and post-operative results of treatment. Firstly, the reliability of the protocol was tested in healthy adult subject. Secondly, a reference group of 15 healthy teenagers was analysed Besides, first scoliotic subject in pre- and post-operative situations were followed. The markers fixed on the skin allowed us to calculate the position of the head, the pelvic, the shoulders and the spinal axis, during a static trial and motions. RESULTS: The reliability of the protocol was satisfactory (standard deviation (s) < 5.4 degrees in a flexion movement). The inter-subject variability was greater for the position of the head than for the pelvis, the shoulders or the spinal axis. The scoliotic patient showed a straightening of the whole body in the three anatomic planes. One month after treatment, the range of motion were reduced (+13.8 degrees for the pelvic flexion during a flexion movement), but six months after surgery they were greater than before (+14.7 degrees). CONCLUSION-DISCUSSION: Many systems have been proposed to measure the motion of the trunk, but they were not three-dimensional. The opto-electronic method is a non invasive, external and dynamic system. 相似文献
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Summary After various attempts, an equivalence relation is defined for labelled Petri nets, on the base of the concurrency semantics of net theory. This relation, called Fully Concurrent bisimulation and abbreviated FC-bisimulation, preserves the level of concurrency of visible operations and, under some conditions, allows to enforce injective labelling on them. Refinements of a visible operation are also defined and we show that, under some conditions, they preserve FC-bisimulation.Research partly supported by ESPRIT Basic Research Action, project 3148: DEMON 相似文献