全文获取类型
收费全文 | 2220篇 |
免费 | 136篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 31篇 |
综合类 | 5篇 |
化学工业 | 624篇 |
金属工艺 | 62篇 |
机械仪表 | 37篇 |
建筑科学 | 195篇 |
矿业工程 | 4篇 |
能源动力 | 85篇 |
轻工业 | 179篇 |
水利工程 | 16篇 |
石油天然气 | 7篇 |
无线电 | 165篇 |
一般工业技术 | 443篇 |
冶金工业 | 88篇 |
原子能技术 | 12篇 |
自动化技术 | 406篇 |
出版年
2023年 | 28篇 |
2022年 | 54篇 |
2021年 | 78篇 |
2020年 | 48篇 |
2019年 | 68篇 |
2018年 | 53篇 |
2017年 | 56篇 |
2016年 | 86篇 |
2015年 | 87篇 |
2014年 | 106篇 |
2013年 | 162篇 |
2012年 | 138篇 |
2011年 | 195篇 |
2010年 | 103篇 |
2009年 | 133篇 |
2008年 | 142篇 |
2007年 | 130篇 |
2006年 | 102篇 |
2005年 | 82篇 |
2004年 | 82篇 |
2003年 | 51篇 |
2002年 | 59篇 |
2001年 | 31篇 |
2000年 | 34篇 |
1999年 | 29篇 |
1998年 | 17篇 |
1997年 | 20篇 |
1996年 | 25篇 |
1995年 | 21篇 |
1994年 | 15篇 |
1993年 | 13篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 16篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 4篇 |
1970年 | 3篇 |
1969年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有2359条查询结果,搜索用时 15 毫秒
61.
Jens Vygen 《Information Processing Letters》2011,111(21-22):1075-1079
62.
Matthias B. StuartAuthor Vitae Jens SparsøAuthor Vitae 《Microprocessors and Microsystems》2011,35(7):632-642
This paper presents an analytical method to derive the worst-case traffic pattern caused by a task graph mapped to a cache-coherent shared-memory system. Our analysis allows designers to rapidly evaluate the impact of different mappings of tasks to IP cores on the traffic pattern. The accuracy varies with the application’s data sharing pattern, and is around 65% in the average case and 1% in the best case when considering the traffic pattern as a whole. For individual connections, our method produces tight worst-case bandwidths. 相似文献
63.
Jens Lincke Malte Appeltauer Bastian Steinert Robert Hirschfeld 《Science of Computer Programming》2011,76(12):1194-1209
Context-oriented programming (COP) provides dedicated support for defining and composing variations to a basic program behavior. A variation, which is defined within a layer, can be de-/activated for the dynamic extent of a code block. While this mechanism allows for control flow-specific scoping, expressing behavior adaptations can demand alternative scopes. For instance, adaptations can depend on dynamic object structure rather than control flow. We present scenarios for behavior adaptation and identify the need for new scoping mechanisms. The increasing number of scoping mechanisms calls for new language abstractions representing them. We suggest to open the implementation of scoping mechanisms so that developers can extend the COP language core according to their specific needs. Our open implementation moves layer composition into objects to be affected and with that closer to the method dispatch to be changed. We discuss the implementation of established COP scoping mechanisms using our approach and present new scoping mechanisms developed for our enhancements to Lively Kernel. 相似文献
64.
Jens Jägersküpper 《Algorithmica》2011,59(3):409-424
In their seminal article Droste, Jansen, and Wegener (Theor. Comput. Sci. 276:51–82, 2002) consider a basic direct-search heuristic with a global search operator, namely the so-called (1+1) Evolutionary Algorithm
((1+1) EA). They present the first theoretical analysis of the (1+1) EA’s expected runtime for the class of linear functions
over the search space {0,1}
n
. In a rather long and involved proof they show that, for any linear function, the expected runtime is O(nlog n), i.e., that there are two constants c and n′ such that, for n≥n′, the expected number of iterations until a global optimum is generated is bounded above by c⋅nlog 2
n. However, neither c nor n′ are specified—they would be pretty large. Here we reconsider this optimization scenario to demonstrate the potential of
an analytical method that makes use of the distribution of the evolving candidate solution over the search space {0,1}
n
. Actually, an invariance property of this distribution is proved, which is then used to obtain a significantly improved bound
on the drift, namely the expected change of a potential function, here the number of bits set correctly. Finally, this better
estimate of the drift enables an upper bound on the expected number of iterations of 3.8nlog 2
n+7.6log 2
n for n≥2. 相似文献
65.
Jens MaßbergJan Schneider 《Theoretical computer science》2011,412(50):6948-6958
We formulate a generalization of the NP-complete rectangle packing problem by parameterizing it in terms of packing density, the ratio of rectangle areas, and the aspect ratio of individual rectangles. Then we show that almost all restrictions of this problem remain NP-complete and identify some cases where the answer to the decision problem can be found in constant time. 相似文献
66.
The evolution and maintenance of large-scale software systems requires first an understanding of its architecture before delving
into lower-level details. Tools facilitating the architecture comprehension tasks by visualization provide different sets
of configurable, graphical elements to present information to their users. We conducted a controlled experiment that exemplifies
the critical role of such graphical elements when aiming at understanding the architecture. In our setting, a different configuration
of graphical elements had significant influence on program comprehension tasks. In particular, a 63% gain in effectiveness
in architectural analysis tasks was achieved simply by changing the configuration of the graphical elements of the same tool.
Based on the results, we claim that significant effort should be spent on the configuration of architecture visualization
tools and that configurability should be a requirement for such tools.
Jens Knodel is a scientist at the Fraunhofer Institute for Experimental Software Engineering (IESE) in Kaiserslautern, Germany. As an applied researcher in the department “Product Line Architectures” he works in several industrial and research projects in the context of product line engineering and software architectures. His main research interests are architecture compliance checking, software evolution, and architecture reconstruction. Jens Knodel is the architect of the Fraunhofer SAVE tool (the acronym SAVE stands for Software Architecture Evaluation and Visualization). Dirk Muthig heads the division “Software Development” at the Fraunhofer Institute for Experimental Software Engineering (IESE). He has been involved in the definition, development, and transfer of Fraunhofer PuLSE (Product Line Software Engineering) methodology since 1997. Further, he leads the research and technology transfer in the area of “Software and Systems Architecture”. He received a diploma in computer science, as well as a Ph.D., from the Technical University of Kaiserslautern. Matthias Naab is an engineer at the Fraunhofer Institute for Experimental Software Engineering (IESE). He works in the areas of software- and system architectures and product lines. In several industry projects, he was involved in architecture evaluations of large-scale information systems from different industries and customers. To the Fraunhofer SAVE tool, he contributed the visualization component. Matthias Naab received a diploma in computer science from the Technical University of Kaiserslautern in 2005. 相似文献
Matthias Naab (Corresponding author)Email: |
Jens Knodel is a scientist at the Fraunhofer Institute for Experimental Software Engineering (IESE) in Kaiserslautern, Germany. As an applied researcher in the department “Product Line Architectures” he works in several industrial and research projects in the context of product line engineering and software architectures. His main research interests are architecture compliance checking, software evolution, and architecture reconstruction. Jens Knodel is the architect of the Fraunhofer SAVE tool (the acronym SAVE stands for Software Architecture Evaluation and Visualization). Dirk Muthig heads the division “Software Development” at the Fraunhofer Institute for Experimental Software Engineering (IESE). He has been involved in the definition, development, and transfer of Fraunhofer PuLSE (Product Line Software Engineering) methodology since 1997. Further, he leads the research and technology transfer in the area of “Software and Systems Architecture”. He received a diploma in computer science, as well as a Ph.D., from the Technical University of Kaiserslautern. Matthias Naab is an engineer at the Fraunhofer Institute for Experimental Software Engineering (IESE). He works in the areas of software- and system architectures and product lines. In several industry projects, he was involved in architecture evaluations of large-scale information systems from different industries and customers. To the Fraunhofer SAVE tool, he contributed the visualization component. Matthias Naab received a diploma in computer science from the Technical University of Kaiserslautern in 2005. 相似文献
67.
Offshore outsourcing to vendors in foreign countries causes unique challenges which need to be understood and managed effectively.
This paper explores cultural differences in IS offshoring arrangements involving German client organizations that outsource
application development activities to Indian vendors. For this purpose, a research framework is developed based on both theoretical
considerations and specific empirical observations from multiple case studies. The goal is to (1) explore the nature of cultural
differences in offshore outsourcing arrangements in depth and to (2) analyze the relationship between those cultural differences
and offshore outsourcing success. Based on the case findings, implications and practices for the management of offshore development
projects are outlined. The results indicate that cultural differences in terms of power distance, IS designer values, and
an active versus passive working attitude critically affect several dimensions of relationship quality, thereby influencing
offshore outsourcing success. A clear definition of roles and mechanisms, strong leadership, and an active management of culture
by adapting to either the client’s or the vendor’s national culture appeared to be effective ways to manage cultural differences.
相似文献
Armin HeinzlEmail: |
68.
69.
Helmut Neukirchen Benjamin Zeiss Jens Grabowski 《International Journal on Software Tools for Technology Transfer (STTT)》2008,10(4):309-326
Experience with the development and maintenance of large test suites specified using the Testing and Test Control Notation (TTCN-3) has shown that it is difficult to construct tests that are concise with respect to quality aspects such as maintainability
or usability. The ISO/IEC standard 9126 defines a general software quality model that substantiates the term “quality” with
characteristics and subcharacteristics. The domain of test specifications, however, requires an adaption of this general model.
To apply it to specific languages such as TTCN-3, it needs to be instantiated. In this paper, we present an instantiation
of this model as well as an approach to assess and improve test specifications. The assessment is based on metrics and the
identification of code smells. The quality improvement is based on refactoring. Example measurements using our TTCN-3 tool
TRex demonstrate how this procedure is applied in practise.
B. Zeiss is supported by a Ph.D. scholarship from Siemens AG, Corporate Technology. 相似文献
70.
Equality and subtyping of recursive types were studied in the 1990s by Amadio and Cardelli; Kozen, Palsberg, and Schwartzbach; Brandt and Henglein; and others. Potential applications include automatic generation of bridge code for multilanguage systems and type-based retrieval of software modules from libraries. In this paper, we present an efficient decision procedure for a notion of type equality that includes unfolding of recursive types, and associativity and commutativity of product types. Advocated by Auerbach, Barton, and Raghavachari, these properties enable flexible matching of types. For two types of size at most n, our algorithm takes O(n) iterations each of which takes O(n) time, for a total of O(n2) time. 相似文献