全文获取类型
收费全文 | 47873篇 |
免费 | 1125篇 |
国内免费 | 187篇 |
专业分类
电工技术 | 575篇 |
综合类 | 644篇 |
化学工业 | 5977篇 |
金属工艺 | 747篇 |
机械仪表 | 981篇 |
建筑科学 | 1062篇 |
矿业工程 | 401篇 |
能源动力 | 622篇 |
轻工业 | 2804篇 |
水利工程 | 638篇 |
石油天然气 | 76篇 |
武器工业 | 6篇 |
无线电 | 2103篇 |
一般工业技术 | 4232篇 |
冶金工业 | 21684篇 |
原子能技术 | 242篇 |
自动化技术 | 6391篇 |
出版年
2024年 | 68篇 |
2023年 | 245篇 |
2022年 | 249篇 |
2021年 | 314篇 |
2020年 | 148篇 |
2019年 | 195篇 |
2018年 | 657篇 |
2017年 | 870篇 |
2016年 | 1256篇 |
2015年 | 929篇 |
2014年 | 647篇 |
2013年 | 820篇 |
2012年 | 2407篇 |
2011年 | 2806篇 |
2010年 | 965篇 |
2009年 | 1036篇 |
2008年 | 866篇 |
2007年 | 828篇 |
2006年 | 753篇 |
2005年 | 3498篇 |
2004年 | 2671篇 |
2003年 | 2168篇 |
2002年 | 965篇 |
2001年 | 807篇 |
2000年 | 343篇 |
1999年 | 657篇 |
1998年 | 6232篇 |
1997年 | 3862篇 |
1996年 | 2551篇 |
1995年 | 1493篇 |
1994年 | 1105篇 |
1993年 | 1137篇 |
1992年 | 264篇 |
1991年 | 316篇 |
1990年 | 316篇 |
1989年 | 295篇 |
1988年 | 306篇 |
1987年 | 240篇 |
1986年 | 217篇 |
1985年 | 188篇 |
1984年 | 82篇 |
1983年 | 95篇 |
1982年 | 140篇 |
1981年 | 193篇 |
1980年 | 203篇 |
1979年 | 74篇 |
1978年 | 109篇 |
1977年 | 618篇 |
1976年 | 1337篇 |
1975年 | 105篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Srinivasulu?Malagari Brian?J.?DriessenEmail author 《Journal of Intelligent and Robotic Systems》2011,62(1):29-58
In this work, we consider a multiple degree of freedom robotic plant with joint hysteresis and without velocity measurement.
We show, by construction, how a semi-globally exponential hysteresis observer/controller that assumes velocity measurement,
a number of which we point out from the literature, can be combined/modified with a velocity observer to yield a combined
semi-globally exponential tracking observer/controller. The resulting observer/controller estimates both the hysteresis state
and the joint velocity. We prove that the combined estimation error and tracking error converges to zero semi-globally exponentially.
One deemed contribution as compared to previous work for this same type of plant is that the usual requirement of velocity
measurement has been removed; another is the proved semi-globally exponential result. 相似文献
992.
Donghai?Guan Weiwei?Yuan Young-Koo?LeeEmail author Sungyoung?Lee 《Applied Intelligence》2011,35(3):345-358
This paper presents a new approach for identifying and eliminating mislabeled training instances for supervised learning algorithms.
The novelty of this approach lies in the using of unlabeled instances to aid the detection of mislabeled training instances.
This is in contrast with existing methods which rely upon only the labeled training instances. Our approach is straightforward
and can be applied to many existing noise detection methods with only marginal modifications on them as required. To assess
the benefit of our approach, we choose two popular noise detection methods: majority filtering (MF) and consensus filtering
(CF). MFAUD/CFAUD is the new proposed variant of MF/CF which relies on our approach and denotes majority/consensus filtering with the aid of unlabeled data. Empirical study validates the superiority of our approach and shows that MFAUD and CFAUD can significantly improve the
performances of MF and CF under different noise ratios and labeled ratios. In addition, the improvement is more remarkable
when the noise ratio is greater. 相似文献
993.
994.
In a 2008 paper, Walmsley argued that the explanations employed in the dynamical approach to cognitive science, as exemplified
by the Haken, Kelso and Bunz model of rhythmic finger movement, and the model of infant preservative reaching developed by
Esther Thelen and her colleagues, conform to Carl Hempel and Paul Oppenheim’s deductive-nomological model of explanation (also
known as the covering law model). Although we think Walmsley’s approach is methodologically sound in that it starts with an
analysis of scientific practice rather than a general philosophical framework, we nevertheless feel that there are two problems
with his paper. First, he focuses only on the deductivenomological model and so neglects the important fact that explanations
are causal. Second, the explanations offered by the dynamical approach do not take the deductive-nomological format, because
they do not deduce the explananda from exceptionless laws. Because of these two points, Walmsley makes the dynamical explanations
in cognitive science appear problematic, while in fact they are not. 相似文献
995.
T. LalinskýAuthor VitaeG. VankoAuthor Vitae M. ValloAuthor Vitae M. Dr?íkAuthor VitaeJ. BrunckoAuthor Vitae J. JakovenkoAuthor VitaeV. KutišAuthor Vitae I. RýgerAuthor VitaeŠ. Haš?íkAuthor Vitae M. HusákAuthor Vitae 《Sensors and actuators. A, Physical》2011,172(2):386-391
We report on a piezoelectric response investigation of AlGaN/GaN circular high electron mobility transistor (C-HEMT) based ring gate capacitor as a new stress sensor device to be potentially applied for dynamic high-pressure sensing. A ring gate capacitor of C-HEMT with an additional ZnO gate interfacial layer was used to measure the changes in the piezoelectric charge induced directly by the variation of piezoelectric polarization of both gate piezoelectric layers (AlGaN, ZnO) for harmonic loading at different excitation frequences. Our experimental results show that about 10 nm thick piezoelectric ZnO layer grown on ring gate/AlGaN interface of C-HEMT can yield almost a 60% increase in the piezoelectric detection sensitivity of the device due to its higher piezoelectric coefficient. A three-dimensional CoventorWare simulation is carried out to confirm the increase in the measured piezoelectric response of ZnO based ring gate capacitor of C-HEMT. 相似文献
996.
Mika HarbeckAuthor Vitae Zafer ?enAuthor Vitae Zafer Ziya ÖztürkAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(2):673-679
Vic-dioximes, a class of organic chemical compounds, are proposed and characterized for the first time as sensitive materials for volatile organic compound sensing with sorption based chemical gas sensors. Their peculiar sensing properties described in this work originate in the oxime functional group which is a powerful H bond donor interacting strongly but reversibly with H bond acceptors. These specific interactions result in a high preferential enrichment of analyte molecules with H bonding acceptor capabilities in the sensitive material. Accordingly, sensitivity and selectivity for these compounds of vic-dioxime based sensors are high. The advantageous sensing properties are demonstrated in this work with quartz crystal microbalance sensors using 11 selected volatile organic compounds and a set of vic-dioximes varied in their substituents. Vic-dioximes with short alkylthiol substituents were found highly sensitive to such H bond acceptors as organic amines, alcohols, and esters with partition coefficients up to 26,000. At the same time they showed low affinity for aromatic compounds and chlorocarbons. Vic-dioximes are considered powerful sensing materials and interesting for practical use in chemical gas sensor arrays. 相似文献
997.
Joanna CabajAuthor VitaeJadwiga So?oduchoAuthor Vitae Antoni ChylaAuthor VitaeAgnieszka J?drychowska 《Sensors and actuators. B, Chemical》2011,157(1):225-231
Electrolytic deposition has been widely used to immobilize biomacromolecules, and it is always the most important factor to preserve or even increase an activity of the immobilized protein. We report here simple and rather universal method for the highly efficient immobilization of laccase for amperometric biosensing. Laccase from Cerrena unicolor has been successfully immobilized (electrolytic deposition) on the surface of thin, ordered polythiophene films (3-methylthiophene/3-thiopheneacetic acid/N-heptyl-3,6-bis(2-thiophene)carbazole). Two different compounds capable of mediating laccase-catalyzed reactions have been tested by cyclic voltammetry. They exhibited quasi-reversible electrodic behaviour with formal redox potentials ranging from 68 and 918 mV (E0vs. SCE). The immersion of the laccase-coated electrode in solution with substrate generated large catalytic currents easily recorded by cyclic voltammetry at low potential scan rates. Considering the fact, that immobilization strategy showed high efficiency, obtained results suggest that method for phenoloxidase immobilization has a great potential of enabling high throughput fabrication of bioelectronics’ devices. 相似文献
998.
Using an asymptotic characterization of probabilistic finite state languages over a one-letter alphabet we construct a probabilistic
language with regular support that cannot be generated by probabilistic CFGs. Since all probability values used in the example
are rational, our work is immune to the criticism leveled by Suppes (Synthese 22:95–116, 1970) against the work of Ellis (1969) who first constructed probabilistic FSLs that admit no probabilistic FSGs. Some implications for probabilistic language
modeling by HMMs are discussed. 相似文献
999.
Emmanuel?FiliotEmail author Naiyong?Jin Jean-Fran?ois?Raskin 《Formal Methods in System Design》2011,39(3):261-296
In this paper, we present new monolithic and compositional algorithms to solve the LTL realizability problem. Those new algorithms are based on a reduction of the LTL realizability problem to a game whose winning condition is defined by a universal automaton on infinite words with a k-co-Büchi acceptance condition. This acceptance condition asks that runs visit at most k accepting states, so it implicitly defines a safety game. To obtain efficient algorithms from this construction, we need several additional ingredients. First, we study the structure
of the underlying automata constructions, and we show that there exists a partial order that structures the state space of
the underlying safety game. This partial order can be used to define an efficient antichain algorithm. Second, we show that the algorithm can be implemented in an incremental way by considering increasing values of k in the acceptance condition. Finally, we show that for large LTL formulas that are written as conjunctions of smaller formulas, we can solve the problem compositionally by first computing winning strategies for each conjunct that appears in the large formula. We report on the behavior of those
algorithms on several benchmarks. We show that the compositional algorithms are able to handle LTL formulas that are several pages long. 相似文献
1000.
The paper deals with the problem of motion planning of anthropomorphic mechanical hands avoiding collisions and trying to
mimic real human hand postures. The approach uses the concept of “principal motion directions” to reduce the dimension of
the search space in order to obtain results with a compromise between motion optimality and planning complexity (time). Basically,
the work includes the following phases: capturing the human hand workspace using a sensorized glove and mapping it to the
mechanical hand workspace, reducing the space dimension by looking for the most relevant principal motion directions, and
planning the hand movements using a probabilistic roadmap planner. The approach has been implemented for a four finger anthropomorphic
mechanical hand (17 joints with 13 independent degrees of freedom) assembled on an industrial robot (6 independent degrees
of freedom), and experimental examples are included to illustrate its validity. 相似文献