全文获取类型
收费全文 | 11533篇 |
免费 | 500篇 |
国内免费 | 71篇 |
专业分类
电工技术 | 218篇 |
综合类 | 83篇 |
化学工业 | 2573篇 |
金属工艺 | 285篇 |
机械仪表 | 270篇 |
建筑科学 | 672篇 |
矿业工程 | 62篇 |
能源动力 | 263篇 |
轻工业 | 1524篇 |
水利工程 | 87篇 |
石油天然气 | 46篇 |
武器工业 | 5篇 |
无线电 | 689篇 |
一般工业技术 | 1785篇 |
冶金工业 | 1609篇 |
原子能技术 | 90篇 |
自动化技术 | 1843篇 |
出版年
2023年 | 84篇 |
2022年 | 163篇 |
2021年 | 217篇 |
2020年 | 162篇 |
2019年 | 165篇 |
2018年 | 253篇 |
2017年 | 191篇 |
2016年 | 290篇 |
2015年 | 262篇 |
2014年 | 355篇 |
2013年 | 706篇 |
2012年 | 494篇 |
2011年 | 624篇 |
2010年 | 503篇 |
2009年 | 487篇 |
2008年 | 515篇 |
2007年 | 509篇 |
2006年 | 412篇 |
2005年 | 345篇 |
2004年 | 339篇 |
2003年 | 272篇 |
2002年 | 320篇 |
2001年 | 263篇 |
2000年 | 205篇 |
1999年 | 192篇 |
1998年 | 307篇 |
1997年 | 222篇 |
1996年 | 174篇 |
1995年 | 159篇 |
1994年 | 146篇 |
1993年 | 151篇 |
1992年 | 147篇 |
1991年 | 95篇 |
1990年 | 105篇 |
1989年 | 91篇 |
1988年 | 104篇 |
1987年 | 77篇 |
1986年 | 62篇 |
1985年 | 90篇 |
1984年 | 103篇 |
1983年 | 66篇 |
1982年 | 73篇 |
1981年 | 90篇 |
1980年 | 76篇 |
1979年 | 90篇 |
1978年 | 73篇 |
1977年 | 74篇 |
1976年 | 64篇 |
1975年 | 69篇 |
1973年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Impacts of green roofs and rain water use on the water balance and groundwater levels in urban areas 总被引:1,自引:0,他引:1
Dr. P. Göbel Prof. Dr. W.G. Coldewey Dr.-Ing. C. Dierkes Dipl.-Math. H. Kories Dr. J. Meßer Dr.-Ing. E. Meißner 《Grundwasser》2007,12(3):189-200
Ohne Zusammenfassung
Impacts of green roofs and rain water use on the water balance and groundwater levels in urban areas
相似文献
102.
In general, the performance of a KE penetrator against most targets increases with velocity regardless of the particular penetrator-target interaction mode. It is possible to show that there exists an optimum velocity which maximizes the performance of an impacting penetrator for a given expenditure of kinetic energy. Simple graphical methods are described that determine the optimum velocity from general performance-velocity plots. These graphical methods may also be applied to experimental data alone. In addition, simple analytic models which describe the velocity dependent penetration/perforation performance of KE penetrators are examined and extended. These models may be used to explicitly assess the influence of parameters such as target strength and density and penetrator mass, strength and density. For some of the models in this analysis, the explicit relations between the optimum striking velocity for a specific kinetic energy value and the penetrator-target parameters are described. 相似文献
103.
Frank Rees 《Computer Fraud & Security》1998,1998(3):11
Much of what has been written in Australia about the protection of computer programs has been inspired by high profile cases concerning the boundaries of copyright protection. The Australian law firm Clayton Utz says that there has been little discussion about other types of legal protection for computer programs, and as a consequence, other intellectual property laws should not be overlooked. 相似文献
104.
Background, prime influences upon present day methods and current trends in United Kingdom tendering practices are reviewed. Significant weaknesses are identified, confirming the need for some revision of existing contractor selection methods. The findings compliment recommendations of the recent government/industry review of the construction sector headed by Sir Michael Latham. Specifically, that tendering procedure should embrace investigation of contractors' potential to deliver a service of acceptable standard, on time, within budget. Present selection methods often fail in this objective, being inclined to discriminate predominantly on cost. 相似文献
105.
106.
A robustness analysis and synthesis for incomplete nonlinear decoupling for a class of nonlinear systems is discussed. Rigid and elastic-joint robot models belong to this class. For the elastic case, a transformation facilitates the robustness analysis under a weak assumption. Charts with H
1- and H
- norms of closed-loop disturbance transfer functions of the nonlinear-decoupled system are presented for a robust pole assignment. 相似文献
107.
Monroe William S. Skidmore Frank M. Odaibo David G. Tanik Murat M. 《Neural computing & applications》2021,33(11):6027-6038
Neural Computing and Applications - In the medical imaging domain, nonlinear warping has enabled pixel-by-pixel mapping of one image dataset to a reference dataset. This co-registration of data... 相似文献
108.
Phan Alex Truong Phuong Schade Christoph Vasan Aditya Friend James Talke Frank E. 《Microsystem Technologies》2021,27(6):2473-2479
Microsystem Technologies - “Zero drift” behavior of an optical intraocular pressure sensor is studied using an analytical model based on the deflection of a circular membrane. Results... 相似文献
109.
David Damm Christian Fremerey Verena Thomas Michael Clausen Frank Kurth Meinard Müller 《International Journal on Digital Libraries》2012,12(2-3):53-71
In this paper, we present a digital library system for managing heterogeneous music collections. The heterogeneity refers to various document types and formats as well as to different modalities, e. g., CD-audio recordings, scanned sheet music, and lyrics. The system offers a full-fledged, widely automated document processing chain: digitization, indexing, annotation, access, and presentation. Our system is implemented as a generic and modular music repository based on a service-oriented software architecture. As a particular strength of our approach, the various documents representing aspects of a piece of music are jointly considered in all stages of the document processing chain. Our user interfaces allow for a multimodal and synchronized presentation of documents (WYSIWYH: what you see is what you hear), a score- or lyrics-based navigation in audio, as well as a cross- and multimodal retrieval. Hence, our music repository may be called a truly cross-modal library system. In our paper, we describe the system components, outline the techniques of the document processing chain, and illustrate the implemented functionalities for user interaction. We describe how the system is put into practice at the Bavarian State Library (BSB) Munich as a part of the German PROBADO Digital Library Initiative (PDLI). 相似文献
110.
Certain tasks, such as formal program development and theorem proving, fundamentally rely upon the manipulation of higher-order objects such as functions and predicates. Computing tools intended to assist in performing these tasks are at present inadequate in both the amount of knowledge they contain (i.e., the level of support they provide) and in their ability to learn (i.e., their capacity to enhance that support over time). The application of a relevant machine learning technique—explanation-based generalization (EBG)—has thus far been limited to first-order problem representations. We extend EBG to generalize higher-order values, thereby enabling its application to higher-order problem encodings.Logic programming provides a uniform framework in which all aspects of explanation-based generalization and learning may be defined and carried out. First-order Horn logics (e.g., Prolog) are not, however, well suited to higher-order applications. Instead, we employ Prolog, a higher-order logic programming language, as our basic framework for realizing higher-order EBG. In order to capture the distinction between domain theory and training instance upon which EBG relies, we extend Prolog with the necessity operator of modal logic. We develop a meta-interpreter realizing EBG for the extended language, Prolog, and provide examples of higher-order EBG. 相似文献