全文获取类型
收费全文 | 1839篇 |
免费 | 204篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 38篇 |
综合类 | 11篇 |
化学工业 | 471篇 |
金属工艺 | 55篇 |
机械仪表 | 31篇 |
建筑科学 | 153篇 |
矿业工程 | 2篇 |
能源动力 | 51篇 |
轻工业 | 66篇 |
水利工程 | 6篇 |
无线电 | 190篇 |
一般工业技术 | 417篇 |
冶金工业 | 105篇 |
原子能技术 | 9篇 |
自动化技术 | 444篇 |
出版年
2024年 | 6篇 |
2023年 | 51篇 |
2022年 | 63篇 |
2021年 | 99篇 |
2020年 | 86篇 |
2019年 | 79篇 |
2018年 | 85篇 |
2017年 | 70篇 |
2016年 | 99篇 |
2015年 | 98篇 |
2014年 | 115篇 |
2013年 | 134篇 |
2012年 | 146篇 |
2011年 | 160篇 |
2010年 | 134篇 |
2009年 | 93篇 |
2008年 | 99篇 |
2007年 | 88篇 |
2006年 | 75篇 |
2005年 | 50篇 |
2004年 | 30篇 |
2003年 | 14篇 |
2002年 | 20篇 |
2001年 | 15篇 |
2000年 | 8篇 |
1999年 | 12篇 |
1998年 | 24篇 |
1997年 | 16篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1991年 | 5篇 |
1988年 | 3篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有2049条查询结果,搜索用时 31 毫秒
41.
42.
The smart car seat: personalized monitoring of vital signs in automotive applications 总被引:1,自引:1,他引:0
Marian Walter Benjamin Eilebrecht Tobias Wartzek Steffen Leonhardt 《Personal and Ubiquitous Computing》2011,15(7):707-715
Embedded wireless sensors are important components of mobile distributed computing networks, and one of the target applications
areas is health care. The preservation of mobility for senior citizens is one of the key issues in maintaining an independent
lifestyle. Thus health technologies inside a car can contribute both to safety issues (supervision of driver fitness) as well
as healthcare issues by monitoring vitals signs imperceptibly. In this paper, three embedded measurement techniques for non-contact
monitoring of vital signals have been investigated. Specifically, capacitive electrocardiogram (cECG) monitoring, mechanical
movement analysis (ballistocardiogram, BCG) using piezo-foils and inductive impedance monitoring were examined regarding their
potential for integration into car seats. All three sensing techniques omit the need for electroconductive contact to the
human body, but require defined mechanical boundary conditions (stable distances or, in the case of BCG, frictional connection).
The physical principles of operation, the specific boundary conditions regarding automotive integration and the results during
wireless operation in a running car are presented. All three sensors were equipped with local intelligence by incorporating
a microcontroller. To eliminate the need for additional cabling, a wireless Bluetooth communication module was added and used
to transmit data to a measurement PC. Finally, preliminary results obtained during test drives on German city roads and highways
are discussed. 相似文献
43.
Stangegaard M Frøslev TG Frank-Hansen R Hansen AJ Morling N 《Journal of laboratory automation》2011,16(2):134-140
We have implemented and validated automated protocols for DNA extraction and PCR setup using a Tecan Freedom EVO liquid handler mounted with the Te-MagS magnetic separation device (Tecan, M?nnedorf, Switzerland). The protocols were validated for accredited forensic genetic work according to ISO 17025 using the Qiagen MagAttract DNA Mini M48 kit (Qiagen GmbH, Hilden, Germany) from fresh whole blood and blood from deceased individuals. The workflow was simplified by returning the DNA extracts to the original tubes minimizing the risk of misplacing samples. The tubes that originally contained the samples were washed with MilliQ water before the return of the DNA extracts. The PCR was setup in 96-well microtiter plates. The methods were validated for the kits: AmpF?STR Identifiler, SGM Plus and Yfiler (Applied Biosystems, Foster City, CA), GenePrint FFFL and PowerPlex Y (Promega, Madison, WI). The automated protocols allowed for extraction and addition of PCR master mix of 96 samples within 3.5h. In conclusion, we demonstrated that (1) DNA extraction with magnetic beads and (2) PCR setup for accredited, forensic genetic short tandem repeat typing can be implemented on a simple automated liquid handler leading to the reduction of manual work, and increased quality and throughput. 相似文献
44.
Tobias Müller Volker Piotter Klaus Plewa Markus Guttmann Hans-Joachim Ritzhaupt-Kleissl Juergen Hausselt 《Microsystem Technologies》2010,16(8-9):1419-1423
Powder injection molding is a preferred technology for the production of micro parts or microstructured parts. Derived from the well known thermoplastic injection molding technique it is suitable for a large-scale production of ceramic and metallic parts without final machining. To achieve good surface quality and control the part size and distortions is an important goal to allow mass production. This means that all process steps like part design adjusted for MIM/CIM-technology, appropriate choice of powder and binder components and injection molding simulation to design the sprue are required. Concerning the injection molding itself high quality mold inserts, high-precision injection molding with suitable molding machines like Battenfeld Microsystem50 or standard machine with special equipment like variotherm or evacuation of the molding tool and an adjusted debinding and sintering process have to be available. Results of producing micro parts by powder injection molding of ceramic feedstock will be presented. 相似文献
45.
Jürgen Bernard Jan Brase Dieter Fellner Oliver Koepler Jörn Kohlhammer Tobias Ruppert Tobias Schreck Irina Sens 《International Journal on Digital Libraries》2010,11(2):111-123
Digital Library support for textual and certain types of non-textual documents has significantly advanced over the last years.
While Digital Library support implies many aspects along the whole library workflow model, interactive and visual retrieval
allowing effective query formulation and result presentation are important functions. Recently, new kinds of non-textual documents
which merit Digital Library support, but yet cannot be fully accommodated by existing Digital Library technology, have come
into focus. Scientific data, as produced for example, by scientific experimentation, simulation or observation, is such a
document type. In this article we report on a concept and first implementation of Digital Library functionality for supporting
visual retrieval and exploration in a specific important class of scientific primary data, namely, time-oriented research
data. The approach is developed in an interdisciplinary effort by experts from the library, natural sciences, and visual analytics
communities. In addition to presenting the concept and to discussing relevant challenges, we present results from a first
implementation of our approach as applied on a real-world scientific primary data set. We also report from initial user feedback
obtained during discussions with domain experts from the earth observation sciences, indicating the usefulness of our approach. 相似文献
46.
Service orientation has been a major buzz-word in recent years. While the buzz is on a decline, organizations are slowly, but steadily moving towards service oriented designs. However, service orientation turns out to be as much of a managerial challenge as of a technical one. The most important complexity drivers in the service oriented design of information systems seem to be (a) inconsistent design goals of stakeholders and (b) the pursuit of exhaustive service orientation coverage. This research focuses on the following two questions: (1) What are the characteristics of successful implementations of service oriented information systems, and (2) what are the critical success factors influencing, driving and/or determining these characteristics? Data of an empirical analysis is used to test a set of cause-effect relationship hypotheses based on nine latent variables. In the core of this model we differentiate the variables ??overall service orientation infrastructure success?? and ??service orientation project success??. The hypothesized interrelationships between the nine variables lead to a causal model which is proven to hold. 相似文献
47.
Koordination in Service Value Networks 总被引:1,自引:1,他引:0
Benjamin Blau Clemens van Dinther Tobias Conte Yongchun Xu Christof Weinhardt 《WIRTSCHAFTSINFORMATIK》2009,51(5):398-413
The fundamental paradigm shift from traditional value chains to agile service value networks implies new economic and organizational challenges. As coordination mechanisms, auctions have proven to perform quite well in situations where intangible and heterogeneous goods are traded. Nevertheless, traditional approaches in the area of multidimensional combinatorial auctions are not quite suitable to enable the trade of composite services. A flawless service execution and therefore the requester’s valuation highly depends on the accurate sequence of the functional parts of the composition, meaning that in contrary to service bundles, composite services only generate value through a valid order of their components. The authors present an abstract model as a formalization of service value networks. The model comprehends a graph-based mechanism implementation to allocate multidimensional service offers within the network, to impose penalties for non-performance and to determine prices for complex services. The mechanism and the bidding language support various types of QoS attributes and their (semantic) aggregation. It is analytically shown that this variant is incentive compatible with respect to all dimensions of the service offer (quality and price). Based on these results, the authors numerically analyze strategic behavior of participating service providers regarding possible collusion strategies. 相似文献
48.
Lutz Hofmann Tobias Fischer Thomas Werner Franz Selbmann Michael Rennau Ramona Ecke Stefan E. Schulz Thomas Geßner 《Microsystem Technologies》2016,22(7):1665-1677
This paper discusses approaches for the isolation of deep high aspect ratio through silicon vias (TSV) with respect to a Via Last approach for micro-electro-mechanical systems (MEMS). Selected TSV samples have depths in the range of 170…270 µm and a diameter of 50 µm. The investigations comprise the deposition of different layer stacks by means of subatmospheric and plasma enhanced chemical vapour deposition (PECVD) of tetraethyl orthosilicate; Si(OC2H5)4 (TEOS). Moreover, an etch-back approach and the selective deposition on SiN were also included in the investigations. With respect to the Via Last approach, the contact opening at the TSV bottom by means of a specific spacer-etching method have been addressed within this paper. Step coverage values of up to 74 % were achieved for the best of those approaches. As an alternative to the SiO2-isolation liners a polymer coating based on the CVD of Parylene F was investigated, which yields even higher step coverage in the range of 80 % at the lower TSV sidewall for a surface film thickness of about 1000 nm. Leakage current measurements were performed and values below 0.1 nA/cm2 at 10 kV/cm were determined for the Parylene F films which represents a promising result for the aspired application to Via Last MEMS-TSV. 相似文献
49.
The Swiss avalanche bulletin is produced twice a day in four languages. Due to the lack of time available for manual translation, a fully automated translation system is employed, based on a catalogue of predefined phrases and predetermined rules of how these phrases can be combined to produce sentences. Because this catalogue of phrases is limited to a small sublanguage, the system is able to automatically translate such sentences from German into the target languages French, Italian and English without subsequent proofreading or correction. Having been operational for two winter seasons, we assess here the quality of the produced texts based on two different surveys where participants rated texts from real avalanche bulletins from both origins, the catalogue of phrases versus manually written and translated texts. With a mean recognition rate of 55 %, users can hardly distinguish between the two types of texts, and give very similar ratings with respect to their language quality. Overall, the output from the catalogue system can be considered virtually equivalent to a text written by avalanche forecasters and then manually translated by professional translators. Furthermore, forecasters declared that all relevant situations were captured by the system with sufficient accuracy. Forecaster’s working load did not change with the introduction of the catalogue: the extra time to find matching sentences is compensated by the fact that they no longer need to double-check manually translated texts. The reduction of daily translation costs is expected to offset the initial development costs within a few years. 相似文献
50.
Given a
-complete (semi)lattice
, we consider
-labeled transition systems as coalgebras of a functor
(−), associating with a set X the set
X of all
-fuzzy subsets. We describe simulations and bisimulations of
-coalgebras to show that L(−) weakly preserves nonempty kernel pairs iff it weakly preserves nonempty pullbacks iff L is join infinitely distributive (JID).Exchanging
for a commutative monoid
, we consider the functor
(−)ω which associates with a set X all finite multisets containing elements of X with multiplicities m M. The corresponding functor weakly preserves nonempty pullbacks along injectives iff 0 is the only invertible element of
, and it preserves nonempty kernel pairs iff
is refinable, in the sense that two sum representations of the same value, r1 + … + rm = c1 + … + cn, have a common refinement matrix (m(i, j)) whose k-th row sums to rk and whose l-th column sums to cl for any 1≤ k ≤ m and 1 ≤ l ≤ n. 相似文献