全文获取类型
收费全文 | 191篇 |
免费 | 3篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 41篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
建筑科学 | 5篇 |
矿业工程 | 4篇 |
能源动力 | 14篇 |
轻工业 | 10篇 |
水利工程 | 1篇 |
无线电 | 25篇 |
一般工业技术 | 46篇 |
冶金工业 | 17篇 |
原子能技术 | 1篇 |
自动化技术 | 26篇 |
出版年
2023年 | 2篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 13篇 |
2012年 | 14篇 |
2011年 | 13篇 |
2010年 | 3篇 |
2009年 | 7篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 12篇 |
2004年 | 10篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 3篇 |
排序方式: 共有194条查询结果,搜索用时 0 毫秒
81.
82.
OBJECTIVES: The current need to evaluate necessity and cost of diagnostic and therapeutic procedures extends to transplant services. We reviewed our experience over the past 3 years as we have moved away from routine post-transplant nuclear medicine scans, ultrasounds, and cystograms. METHODS: From January 1, 1992 to December 31, 1994, 252 kidney transplants were performed at Virginia Mason Medical Center. There were 74 live donor and 178 cadaver donor kidneys transplanted. The records of these patients were reviewed for the type and number of post-transplant imaging done during their initial hospitalization. RESULTS: During the study period, the number of post-transplant imaging studies per patient decreased from 2.7 to 1.4 (P = 0.000), the percentage of patients discharged without any studies rose from 2.8% to 24.4% (P = 0.001), and the trend in 1-year actual graft survival increased from 84.7% to 93.0% (P = 0.187). CONCLUSIONS: Post-transplant imaging studies can be safely reduced. Many patients with good initial graft function can avoid having any studies. 相似文献
83.
Evolvability is widely considered to be a crucial characteristic of software architectures, particularly in the area of information systems. Although many approaches have been proposed for improving evolvability, most indications are that it remains challenging to deliver the required levels of evolvability. In this paper, we present a theoretical approach to how the concept of systems theoretic stability can be applied to the evolvability of software architectures of information systems. We define and formalize the transformation of a set of basic functional requirements into a set of instantiations of software constructs. We define this transformation using both a static and a dynamic perspective. In the latter perspective, we formulate the postulate that information systems should be stable against new requirements. Based on this postulate, we derive a number of design theorems for software implementation. Using this transformation we use theoretical arguments to derive that these theorems contribute to achieving stability. 相似文献
84.
Josephson tunnel junctions were fabricated on niobium by ion-beam oxidation where an oxide thickness independent of the processing time can be achieved. Low specific capacitance of about 5 µF/ cm2at a maximum current density of 1 kA/cm2have been measured via junction and interferometer resonances. A model for the structure of those low-capacitance barriers is proposed. 相似文献
85.
Advances in the technologies of sensors and lightweight robots increasingly enable direct physical interaction between humans and robots. This so-called human–robot collaboration is supposed to offer more flexibility in production processes, as opposed to fully automated processes. The aim of this contribution is to describe an integer linear programming model which optimally coordinates the distribution of tasks between humans and robots in a realistic production process of printed circuit boards (PCBs), where the objective is to minimise the completion time of a board. In addition, we discuss an extended case wherein a whole set of different boards is to be assembled, which is highly relevant for low volume production with a high degree of customisation. After stating an extended integer linear programming (ILP) formulation, we propose two practical approaches for solving the computationally more complex second scenario: an order-based heuristic approach and a matheuristic applying a truncated variant of the ILP model with different sequencing strategies. The computational evaluation based on a real-world use case from the PCB industry underlines the efficacy of the matheuristic approach for obtaining a good overall makespan. 相似文献
86.
A DNA‐Encoded Library of Chemical Compounds Based on Common Scaffolding Structures Reveals the Impact of Ligand Geometry on Protein Recognition 下载免费PDF全文
Nicholas Favalli Stefan Biendl Marco Hartmann Dr. Jacopo Piazzi Dr. Filippo Sladojevich Dr. Susanne Gräslund Dr. Peter J. Brown Dr. Katja Näreoja Prof. Dr. Herwig Schüler Dr. Jörg Scheuermann Prof. Dr. Raphael Franzini Prof. Dr. Dario Neri 《ChemMedChem》2018,13(13):1303-1307
A DNA‐encoded chemical library (DECL) with 1.2 million compounds was synthesized by combinatorial reaction of seven central scaffolds with two sets of 343×492 building blocks. Library screening by affinity capture revealed that for some target proteins, the chemical nature of building blocks dominated the selection results, whereas for other proteins, the central scaffold also crucially contributed to ligand affinity. Molecules based on a 3,5‐bis(aminomethyl)benzoic acid core structure were found to bind human serum albumin with a Kd value of 6 nm , while compounds with the same substituents on an equidistant but flexible l ‐lysine scaffold showed 140‐fold lower affinity. A 18 nm tankyrase‐1 binder featured l ‐lysine as linking moiety, while molecules based on d ‐Lysine or (2S,4S)‐amino‐l ‐proline showed no detectable binding to the target. This work suggests that central scaffolds which predispose the orientation of chemical building blocks toward the protein target may enhance the screening productivity of encoded libraries. 相似文献
87.
Zlatka K. Avramova Danny De Vleeschauwer Pedro Debevere Sabine Wittevrongel Peter Lambert Rik Van de Walle Herwig Bruneel 《Multimedia Tools and Applications》2012,57(3):605-631
Video broadcast operators target a variety of receiving devices of different resolutions and processing capabilities. In such
a heterogeneous TV network, the transport resource consumption is likely to increase. In this paper we estimate the required
transport capacity for a broadcast TV network taking into account parameters as currently proposed in standardization bodies.
We target constant video quality, hence the TV channel has variable bit rate (VBR). We consider a multicast-based transport
system where only the required versions of a TV channel are transported; this leads to fluctuation of the consumed transport
capacity over time. The main focus in this paper is on the comparison of a simulcast and a scalable video coding (SVC) transport
scheme in several realistic examples with different encoding modes, including spatial and/or quality scalability. To estimate
the required transport capacity for simulcast and SVC, we use a comprehensive toolkit based on a Gaussian approximation of
the capacity demand. In order to obtain realistic input values for our calculation tools, we characterize the fluctuations
of the bit rate associated with a TV channel by encoding a representative set of video clips. Based on the considered realistic
examples, we explore under what conditions either the simulcast or the SVC transport scheme is more efficient. 相似文献
88.
89.
Br?der Arndt; Herwig Andrea; Teipel Stefan; Fast Kristina 《Canadian Metallurgical Quarterly》2008,23(2):353
The authors compared patients with mild cognitive impairment with healthy older adults and young control participants in a free recall test in order to locate potential qualitative differences in normal and pathological memory decline. Analysis with an extended multitrial version of W. H. Batchelder and D. M. Riefer's (1980) pair-clustering model revealed globally decelerated learning and an additional retrieval deficit in patients with mild cognitive impairment but not in healthy older adults. Results thus suggest differences in memory decline between normal and pathological aging that may be useful for the detection of risk groups for dementia, and they illustrate the value of model-based disentangling of processes and of multitrial tests for early detection of dementia. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
90.
Koen De Turck Stijn De Vuyst Dieter Fiems Herwig Bruneel Sabine Wittevrongel 《Wireless Networks》2013,19(5):831-842
There is a considerable interest nowadays in improving energy efficiency of wireless telecommunications. The sleep-mode mechanism in WiMAX (IEEE 802.16) and the discontinuous reception (DRX) mechanism of LTE are prime examples of energy saving measures. Recently, Samsung proposed some modifications on the sleep-mode mechanism, scheduled to appear in the forthcoming IEEE 802.16m standard, aimed at minimizing the signaling overhead. In this work, we present a performance analysis of this proposal and clarify the differences with the standard mechanism included in IEEE 802.16e. We also propose some special algorithms aimed at reducing the computational complexity of the analysis. 相似文献